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Purveyors of Electronic, Musical and Vintage goods from then, now and in between. 
Since 1982.

FULLY SERVICED / RESTORED W/ WARRANTY*
VINTAGE STEREO RECEIVERS
SERVICED / RESTORED CLASSICS 


Vintage Stereo Receivers & Used Stereo Receivers for sale that have been Refurbished. Brands / models of Classic / Vintage Stereo Receivers, 'Old-School' / 2-Channel stereo receivers, and Quadraphonic / Quad AM/FM receivers (sometimes referred to as "Radios" and / or "Tuners") such as Kenwood KR, MCS, Pioneer SX / Pioneer SX-1980 for sale, Sansui G, Sony STR, Yamaha CR and Stereo / home audio receivers from the 1960's, 1970's & 1980's.


 

(*UNLESS OTHERWISE LISTED)
 

CLASSIC 2-CHANNEL & 4-CHANNEL STEREO RECEIVERS & QUADRAPHONIC RECEIVERS . . .

 


 





NEW LISTING
6/21/19
(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
STEREO / QUADRAPHONIC
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE STEREO RECEIVER SANSUI QUADRAPHONIC / 4-CHANNEL / 2-CHANNEL STEREO RECEIVER
SANSUI QRX-6500 RECEIVER
#...0464
Circa 1973-75
"WORLD AC POWER"
 M.I.J.
for sale


ü  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is above average for a 'stereo receiver' on this SANSUI QRX-6500. 

ü  Most lamps; dial, Stereo indicator, 2/4 Channel indicator, "Discrete", 2-Channel Aux, 'FM', 'Phono-1', Stereo Decoder & meter lamps 'proactively' replaced for a TOTAL OF 19!!!

ü This unit utilizes 'Mica' output transistor insulators, do no heat sink compound to worry about drying up.

ü Amplifier section had output bias adjusted to spec levels of ~25-30mVDC on all four amplifiers.

ü NOW all 4 amplifiers have 'even' clipping on 'plus' and 'minus' rails.

ü  DC offset adjusted to VERY LOW levels (<10mVDC) on all four amplifiers.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 17 hours
.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.
 
ü On our test bench, this particular QRX-6500, #...0464, 'FRONT' amplifiers each produced 19.4 Volts per channel for 47 Watts per channel @ 8Ω via discrete output & 16.4 Volts per channel for 66+ Watts per channel @ 4Ω
and
ü REAR' amplifiers each produced 17.5 Volts per channel for 38+ Watts per channel @ 8Ω via discrete output & 15 Volts per channel for 56 Watts per channel @ 4Ω
via discrete, Metal cased, TO-3 outputs.
ü AC draw at idle .4A tested.
ü DC Offset adjusted and measured down to <10mVDC any one channel
ü Floor noise measured at >60dBm / 0.1mVAC
 ___________________________

 

HUGE and VERY IMPRESSIVE looking, Sansui, brushed silver, QUAD receiver, surrounded by handsome, real Walnut wood veneer side plates.  Features gorgeous, back-lit slide rule analog tuning scale with matching VU meters as well. VERY elegant and IMPRESSIVE unit when lit in a darkened room. 'Heavy' built, machined aluminum knobs and button caps, also make this unit a pleasure to 'feel'. This receiver is a 'blast' to use and listen to.

Sansui QRX-6500 Features include
:
  

- Quadraphonic (sometimes spelled "quadriphonic" or "quadrophonic") / Stereo receiver 
- Weighted flywheel analog tuning
- A, B, C Off or A+B or A+C Front speaker positions
- A, B, Off or A+B Rear speaker positions
- Separate Front and Rear, Bass and Treble controls
- Balance controls allow complete blending between Front and Rear / Left and Right
 - Built-in Hi and Sub filters (separately switchable Front and Rear) for reducing 19kHz pilot tone in FM broadcasts, Tape Hiss and the Sub filter for reducing turntable rumble
- FM Stereo / Mono (separate from 'FM Muting' selector)
- FM muting (separate from 'Stereo' selector)
- Mode Selector (EXTENSIVE SELECTION) for Stereo / Mono / 2-Channel / 4-Channel and more...

- ''Synthesizer / Decoder Function Control' selector for 2-Channel Stereo, & 4-Channel modes of ''QS Synthesizer' (To convert (synthesize) conventional, 2-channel / stereo program sources to 4-Channel stereo output),
Hall; "To enjoy the kind of 'presence' you'd feel if you were seated front and center in a concert hall, theater, or jazz club..."
Surround; "To drown yourself in the middle of the music. The performing artists will surround you, making you feel as if you were participating."

'QS Regular Matrix' (to decode and reproduce 4-channel program sources (records, tapes and their respective broadcasts), 
''Phase Matrix' (to decode and reproduce 4-channel program sources, encoded with the CBS / SQ matrix system)
or
'CD-4 / Discrete' (when wishing to hear discrete 4-channel tapes or CD-4 (Quadradisc) records).
- Aux inputs for both Front and Rear (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Dual tape monitors with Tape monitor A also featuring a DIN input as well as the standard RCA I/O's for both Front and Rear
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
-  Dual Phono / Turntable inputs with Built-In Phono Pre-Amp, featuring 'Phono-2' compatible with 'CD-4' cartridges

- Separate Front and / or Rear Loudness control for increasing 'rock-n-roll smile' tone curve at lower volumes
- Front and Rear 1/4" stereo headphone jacks for connection of either 'stereo' headphones, or 'quadraphonic / 4-channel' headphones
- Dual Tuning DArsonval meters for tuning and signal strength

 - AM Local / Distant selector on rear panel

- Rear located, full barrier strip for external antenna connections
- Rear located main AC protection fuse
 - 4 Externally mounted speaker protection fuses on rear panel
- Triple AC convenience outlets on rear panel with 1 switched and 1 un-switched for a total capacity of 250 Watts of accessories
  - True “
WORLD AC POWER"

   as it will work on both 50 or 60 Hz AC and voltages from 110-240 Volts AC


Sansui QRX-6500 Original Specs:

 POWER / PRE AMP SPECIFICATIONS:
THD;
0.5% @ full rated power @ 1kHz.
Power bandwidth of power amp section; 20-30,000Hz ±0dB
 IMD utilizing AUX;
 0.5% @ full rated power / 20-20kHz and 8 Ohms
 Damping factor; 30 @ 8Ω full bandwidth
Dynamic (music) rated Power: 2 x 190 Watts @ 8 Ohms or 280 Watts @ 4 Ohms
Cont rated Power:

4x 33 Watts @ 8 Ohms / 1kHz (ALL channels driven w/ 1kHz input)

4x 37 Watts @ 8 Ohms / 1kHz (each channel driven w/ 1kHz input)

4x 60 Watts @ 4 Ohms / 1kHz (each channel driven w/ 1kHz input)

Hum and Noise; >70dB on AUX / Tape
Input Sensitivity AUX / Tape; 150mV @ 50kΩ
Record Out Levels; 150mV
Bass Control;  ±15dB @ 50hz (most amp tone controls are only +/- 10dB)
Treble Control;  ±15dB @ 20khz (most amp tone controls are only +/- 10dB)
Low Filter;  -10dB @ 50Hz @ 6dB Oct
High Filter;  -10dB @ 10kHz @ 6dB Oct
"Loudness" Contour;  +8dB @ 50hz, +3dB @ 10khz (w/ volume set at -30dB)

TUNER SPECS FOR FM:
Tuning Range;
88-108MHz
Freq Response;
30-15kHz (limited by FCC)
S/N; > 65db Stereo w/ 1mV input
Mono Sensitivity; 1.8 μV
Capture Ratio; <1.5dB
IF Rejection; >100dB
Image Rejection; >100dB
Spurious Noise Ratio; >100dB
Selectivity; >70dB
THD w/ 100% modulation Mono; 0.5%
THD w/ 100% modulation Stereo; 0.8%
Stereo Separation; >35dB

TUNER SPECS FOR AM:
Tuning Range;
535-1605kHz
Useable Sensitivity; 50db/m with ferrite stick antenna
Image Rejection; >100dB
IF Rejection; >100dB
Selectivity; 30dB

PHONO SECTION SPECS:
Freq Response;
30-15kHz RIAA Standard Curve +/- 1dB.

S/N;
>60 dB
Input Sensitivity;
2.5 mV @ 50kΩ
Overload limit;
150mV w/ 0.5% THD @ 1kHz

 Power consumption;
150 Watts at rated
  

Again, as stated before, we have completely gone through this SANSUI QRX-6500 Quad receiver, cleaning and testing all and it gets our full
'Certification'. Everything is in fabulous electrical and cosmetic condition! Looks near new and sounds great! AMAZING looking when lit up at night or in a darkened room! Again, this unit is a 'blast' to use. It just simply 'feels nice'!
Comes with an 'e-copy / PDF download of the SANSUI QRX-6500 owners / users / service manual, and brochure if the purchaser desires.  Measures 21.2" wide x 7.25" tall x 14.5" deep and weighs an impressive 49 lbs unpacked. Includes our standard 90 day limited warranty.
SANSUI QRX-6500 STEREO RECEIVER
Cond. 8.5+++
$1199.

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 
 


 

    



NEW LISTING
6/21/19
(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
STEREO / QUADRAPHONIC
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE STEREO RECEIVER SANSUI QUADRAPHONIC / 4-CHANNEL / 2-CHANNEL STEREO RECEIVER
SANSUI QR-4500 RECEIVER
#...0983
Circa 1973-75
"WORLD AC POWER"
M.I.J.
for sale


ü Our technician has completely gone through and 'Certified' this unit.

ü We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is above average for a 'stereo receiver' on this SANSUI QR-4500. 

ü All dial, indicator & meter lamps checked. Dial and meter lamps replaced w/ original spec 6.3V / 250mA.

ü We also checked the heat sink compound which should be good for another 30 years.

ü Driver boards removed and had their 'edge connectors' burnished.

ü Amplifier section had output bias adjusted to service manual spec levels of on all four amplifiers.

ü NOW all 4 amplifiers have 'even' clipping on 'plus' and 'minus' rails.

ü DC offset adjusted to VERY LOW levels on all four amplifiers.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 12+ hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.
 
ü On our test bench, this particular QR-4500, #...0983, 'FRONT and REAR' amplifiers each produced 15.5 Volts per channel for 30 Watts (160 WPC peak) per channel @ 8Ω via discrete output & 13Volts per channel for 42 Watts (240 WPC peak) per channel @ 4Ω via discrete, Metal cased, TO-3 outputs.
ü AC draw at idle .3A tested. DC 10-15mV any single channel.
ü Floor noise measured at >-60dBm / 0.1mVAC
 ___________________________

 
HUGE and VERY IMPRESSIVE looking, Sansui, brushed silver, QUAD receiver, surrounded by handsome, real Walnut wood veneer side plates. This unit has about THE highest 'KPD-Factor' of any we've had in a long time. What's a 'KPD Factor'? You'll find out when you call to order it.
Features gorgeous, back-lit slide rule analog tuning scale with matching VU meters as well. VERY elegant and IMPRESSIVE unit when lit in a darkened room. 'Heavy' built, machined aluminum knobs and button caps, also make this unit a pleasure to 'feel'. One of the most 'fun' receivers I've used in a long time.

Regarding some of the 'Quad' aspects, from the original Sansui QR-4500 brochure,
"It's exclusive, built-in, 2-4 Synthesizer Encoder helps the QS regular matrix system convert all of your 2-channel / stereo records, tapes and FM stereo broadcasts into more exciting 4-channel sound than ever.  It has 'Phase Matrix' circuitry that takes advantage of Sansui's exclusive front-rear logic to decode all SQ system records too, with superb front-rear separation...And for even greater versatility, the unit comes complete with an extra set of discrete 4-channel inputs, permitting you to connect a 'demodulator' to play "discrete" records".

Sansui QR-4500 Features include:
  

- Quadraphonic (sometimes spelled "quadriphonic" or "quadrophonic") / Stereo receiver 
- Weighted flywheel analog tuning
- A, B, Off or A+B Front and Rear speaker positions (separately)
- Separate Bass and Treble controls (front speakers)
- Balance controls allow complete blending between Front and Rear / Left and Right
 - Built-in Hi and Sub filters (separately switchable Front and Rear) for reducing 19kHz pilot tone in FM broadcasts, Tape Hiss and the Sub filter for reducing turntable rumble
- FM muting to reduce 'hiss' in between stations (most handy for trouble-shooting speakers / drivers and system overall)
- ''Function Control' selector for 2-Channel Stereo, & 4-Channel modes of ''QS Synthesizer' (To convert (synthesize) conventional, 2-channel / stereo program sources to 4-Channel stereo output), 'QS Regular Matrix' (to decode and reproduce 4-channel program sources (records, tapes and their respective broadcasts),  ''Phase Matrix' (to decode and reproduce 4-channel program sources, encoded with the CBS / SQ matrix system) or 'CD-4 / Discrete' (when wishing to hear discrete 4-channel tapes or CD-4 (Quadradisc) records).
- Dual Aux inputs for both Front and Rear (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Dual tape monitors with Tape monitor A also featuring a DIN input as well as the standard RCA I/O's for both Front and Rear
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
-  Dual Phono / Turntable inputs with Built-In Phono Pre-Amp, featuring 'Phono-2' compatible with 'CD-4' cartridges
- Loudness control for increasing 'rock-n-roll smile' tone curve at lower volumes
- Pre-Out / Power-Amp In loops on rear panel for all amps
- Front and Rear 1/4" stereo headphone jacks for connection of either 'stereo' headphones, or 'quadraphonic / 4-channel' headphones
- Tuning DArsonval meters for signal strength
 - Front mounted Dual 1/4" stereo headphone jacks
 - 4 Externally mounted speaker protection fuses on rear panel
 - 4 Separate sets of speaker output connectors on rear panel

 - AM Local / Distant selector on rear panel

- Rear located, full barrier strip for external antenna connections

 - Built-in AM Ferrite Stick antenna

- Rear located main AC protection fuse
- Triple AC convenience outlets on rear panel with 1 switched and 2 un-switched for a total capacity of 350 Watts of accessories
  - True “
WORLD AC POWER"

   as it will work on both 50 or 60 Hz AC and voltages from 110-240 Volts AC


Sansui QR-4500 Original Specs:

 POWER / PRE AMP SPECIFICATIONS:
THD;
0.5% @ full rated power
Freq Response of power amp section; 30-30kHz @ 1W
Power bandwidth of power amp section; 20-30,000Hz ±0dB
 IMD utilizing AUX;
<0.5% @ full rated power / 20-20kHz and 8 Ohms
Damping factor; >30 @ 8Ω full bandwidth
Dynamic rated Power: 2 x 160 Watts @ 8 Ohms or 240 Watts @ 4 Ohms
Cont rated Power:
4x 38 Watts @ 8 Ohms / 1kHz (each channel driven)
4x 38 Watts @ 4 Ohms / 1kHz (each channel driven)
4x 23 WPC @ 8 Ohms / 1kHz (ALL channels driven)

Hum and Noise; >70dB on AUX / Tape
Channel Separation; >45dB @ 1kHz @ rated output
Input Sensitivity AUX / Tape; 150mV @ 50kΩ
Record Out Levels; 150mV
Bass Control;  ±15dB @ 50hz (most amp tone controls are only +/- 10dB)
Treble Control;  ±15dB @ 20khz (most amp tone controls are only +/- 10dB)
Low Filter;  -10dB @ 50Hz @ 6dB Oct
High Filter;  -10dB @ 10kHz @ 6dB Oct
"Loudness" Contour;  +8dB @ 50hz, +3dB @ 10khz (w/ volume set at -30dB)
Synthesizer / DecoderSansui 'New QS' circuit / Vario-Matrix


TUNER SPECS FOR FM:
Tuning Range;
88-108MHz
Freq Response;
30-15kHz (limited by FCC)
S/N; > 65db Stereo w/ 1mV input
Mono Sensitivity; 2.0 μV
Capture Ratio; <1.5dB
IF Rejection; >80dB
Image Rejection; >80dB
Spurious Noise Ratio; >90dB
Selectivity; >50dB
THD w/ 100% modulation Mono; 0.5%
THD w/ 100% modulation Stereo; 0.8%
Stereo Separation; >35dB

TUNER SPECS FOR AM:
Tuning Range;
535-1605kHz
Useable Sensitivity; 50db/m with ferrite stick antenna
Image Rejection; >100dB
IF Rejection; >100dB
Selectivity; >30dB

PHONO SECTION SPECS:
Freq Response;
30-15kHz RIAA Standard Curve +/- 1.5dB.

S/N;
>60 dB
Input Sensitivity;
2.5 mV @ 50kΩ
 Overload limit;
150mV w/ 0.5% THD @ 1kHz
  

Again, as stated before, we have completely gone through this Sansui QR-4500 Quad receiver, cleaning and testing all and it gets our full
'Certification'.
Built using super quality, full size, ALPS brand pots. Everything is in fabulous electrical and cosmetic condition! Looks near new and sounds great! AMAZING looking when lit up at night or in a darkened room! Again, this unit is a 'blast' to use. It just simply 'feels nice'!
INCLUDES ORIGINAL BOX & PACKING!!!
Comes with an 'e-copy / PDF download of the Sansui QR-4500 owners / users manual, and the service manual if the purchaser desires. Measures 20.75" wide x 6.75" tall x 12.5" deep and weighs an impressive 41 lbs unpacked. Includes our standard 90 day limited warranty.
SANSUI QR-4500 STEREO RECEIVER
Cond. 9+++
$999.
(Cons. R.R.)

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 
 


 



 

    

NEW LISTING
7/9/19
(Click on above thumbnails to enlarge photos) 
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE PIONEER STEREO RECEIVER
THE CLASSIC PIONEER SX-939 / SX939

Circa 1974-76
#...712M
MIJ

SOLD 9/7/19
SHIPPING TO CHRIS IN OHIO

ü Our technician has completely gone through and 'Certified' this unit.

ü
 Everything was cleaned inside and out including all contacts, switches and controls.

ü Multiple (ALL), 'typically-sticky' push switches removed, overhauled / cleaned and lubed across front

ü Dial glass removed and completely / solidly re-attached

ü Skewed control shafts straightened

ü All dial / meter lamps / bulbs replaced with LED's for trouble-free service

ü Electrolytic power supply filter capacitors tested for leakage

ü All question-able and common 'stress point' solder joints re-flowed

ü All 4 power transistors removed, tested for leakage

ü Bias current adjusted to correct levels.

ü DC offset adjusted to super low levels.

ü We also aligned the tuner 'front-end' for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM reception WAY above average, FM reception incredible, PUNCHY, with GREAT SEPARATION and IMPECCABLY CLEAN!!! due to the 'Pair of Dual-Gate MOS-FETS' FM front end and the quality of the restoration.

ü Tuner 'Station Indicator / pointer' aligned internally for position accuracy as well

ü Entire unit cleaned / detailed cosmetically inside and out. Receiver looks FABULOUS and NEAR NEW!

ü All inputs tested and both sides produce clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifiers / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours and into a 4 Ohm Load!

You will not be disappointed. Total restoration time investment ~10.5 hours.  

ü On our test bench, the internal amplifiers of this Pioneer SX-939 receiver, #...712M produced 27 Volts per channel @ 8 Ohms with 1Khz input for 91 Watts and 24 Volts per channel @ 4 Ohms with 1Khz input for 144 Watts via discrete, TO-3, metal cased outputs (2x NEC 2SB541 & 2x 2SD388).
ü AC Idle current at 400mA,
ü Bias adjusted to correct spec.
ü DC offset output adjusted to < 2.0 mV DC either channel.
ü Floor noise @ >-60dBm AC either channel.
   ____________________________


This is from the series that is commonly referred to as Pioneer's 'Blue Face' receiver offering. Beautiful receiver. Classic looking brushed-aluminum silver face panel, surrounding 'smoked' dial glass, with 'aqua back-lit' enumeration. All encased in a walnut grain, vinyl wrapped, cabinet with solid Walnut wood corner caps. These are SERIOUS receivers and this one has been '
certified' following the refurb by Oak Tree Vintage and is in great condition!!!
 
Pioneer SX-939 Stereo Receiver Features:
 

Tuner features:
- Weighted flywheel analog "slide-rule" tuning
- PLL FM Tuning and 'Dual Mos-Fet' circuitry
- 7 Gang Tuning Capacitor
- Fully Shielded tuner 'Front End'
- FM Muting Selector (separate from the 'Stereo' selector)
- Dual analog 'Signal Strength' and 'Tuning' VU meters
- FM Detector / 4-channel RCA output
- Dual position FM De-emphasis selectable for 50 or 75 msec
- Built-In AM 'Stick / Bar' antenna 

Pre-Amp / 'Control Amplifier' features:
- A, B, C, A+B, A+C, B+C & Off speaker selector (max 2 pair at a time, just with most all receivers / amplifiers to maintain a 4 Ohm minimum)
- Quasi-Quad-Band EQ w/ Sub-Bass, Bass, Treble and Super-Treble controls
- Tone Defeat for purest signal path
- Super quality de-tented Tone and Volume controls
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- Stereo / Mono selector (for entire pre-amp section, not just FM tuner)
- 'Scratch-Filter / Hi filter for reducing tape hiss / electronic hiss & noise and record static
- Built-in 'Low' Filter to eliminate excess rumble from sources such as turntables
--20dB Audio Muting for instant lowering of volume without adjusting the volume control. Great for ringing phones and cuing a record on your turntable

Pioneer SX-939 Inputs:
- Dual Phono / turntable inputs with Built-In Phono Pre-Amps
- Dual tape monitors with Tape monitor 'B' also featuring a DIN input as well as the standard RCA I/O's
(Tape Monitors can be used with Tape / Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Bi-Directional Tape 'Dubbing' capability
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)
- Dolby 'Adaptor' Loop can be used as an additional input or as a signal processor loop for EQ, Dynamic Range Expanders, Reverbs, Delays, DBX units, etc.
- Dual 1/4", stereo headphone jacks
- Dual Phono inputs with phono 2 doubling
- Dual 1/4" front mounted Microphone inputs (be careful with your 'home audio' speakers utilizing 'microphones' with them)

Other:
- Pre-out / Main-in loop (allows feed to an additional / larger power amp, or to 'direct feed' the power-amp in the receiver with another pre-amp or audio mixer)
- Easy 'Serviceable' internal design
- Triple AC 'Convenience' outlets (1 switched / 2 un-switched) with a total capacity of 300 Watts

 
Original Pioneer SX-939 Specifications:


"The SX-939 has a continuous power output of 70 Watts per channel min @ 8 Ohms & 60 wpc @ 4 Ohms, from 20 hertz to 20,000 hertz with no more than 0.3% THD (measured utilizing AUX input)"
 
POWER / PRE AMP SPECIFICATIONS:

THD: 0.3% @ 70 Wpc @ 8 Ohms & THD 0.05% @ 1 wpc @ 8 Ohms
Freq Response of power amp section: @ full rated power 20-20kHz
Potential frequency response of power amp section @ 1w:
7Hz to 100KHz, + 0 dB,- 1 dB
IMD utilizing AUX: 0.3% @ 85 wpc & 0.05% @ 1 wpc @ 8 Ohms
Hum / Noise Ratio: 110dB (10dB increase over the SX-950)
Damping factor:
45 @ 8Ω full bandwidth (almost double the SX-950)
Power Amp Input Impedance:
50k Ohms
Power Amp Input Sensitivity for Full Output:
1V
Headphone: 4-16 Ohms
Tone Control ranges:
Sub Bass: +/-5dB @ 50Hz
Bass:
+/-10dB @ 100Hz
Treble: +/-10dB @ 10kHz
Super Treble: +/-5
dB @ 20kHz
Hi-Cut / Scratch Filter: -9dB  10
KHz, 6dB/octave
Lo Cut Filter: -8dB / 50Hz, 6dB/octave
Loudness Contour w/ vol @-40dB: +8dB at 100 Hz, +4dB at 10KHz
Pre-Amp Input Sensitivity at all inputs except phono & mic:
150mV
Microphone Input Impedance: 2.0mV / 50k Ohms
Input Sensitivity at all inputs except phono & mic:
150mV / 70k Ohms
Input Freq Response (except Phono & Mic): 10Hz-40kHz
Tape Output:
150mV @ RCAs &
30mV @ DIN
Pre-Amp Output Level / Impedance : 1V / 1k Ohms
Pre-Amp THD @ rated output: <0.1%
Pre-Amp S/N @ 'Tape' & 'AUX': >95dB
Pre-Amp S/N @ ''Microphone': >65dB

TUNER SPECS FOR FM

(essentially similar specs on the SX-950 and SX-838):
Freq Response:
20-15kHz (actually beyond FCC regulations)
S/N:
 > 70dB Mono @ 65dBf
Useable Sensitivity (IHF):
1.8μV
Capture Ratio:
1.0dB
De-Emphasis: selectable 50 or 75 μ-sec
THD w/ 100% modulation @ 1kHz, Mono: 
0.2%
THD w/ 100% modulation @ 1kHz, Stereo: 
0.4%
IF Rejection: 
100dB
Stereo Sub-Carrier Rejection: 
65dB
AM Carrier Rejection / Suppression ratio: 55dB
Spurious Rejection:
100 dB

Image Rejection:
85 dB
FM Alternate Channel Selectivity: 
80dB
Stereo Separation:
40dB @ 1kHz

TUNER SPECS FOR AM:

RF Sensitivity: 300uV/meter or 15uV @ binding posts
Alternate Channel Selectivity:
40dB
IF Response Rejection Ratio:
85dB
Image Rejection:
65dB
Signal to Noise Ratio:
50dB


PHONO SECTION SPECS:
Freq Response:
30-15kHz
S/N:
>70dB, ref w/ 10mV input
Input Sensitivity 'Phono-1' or 'Phone-2':
2.5 mV @ 50kΩ
Overload limit:
250mV RMS / 700mV P-P @ 1kHz


Most techs, including myself, who have been inside of the various SX Pioneer series receivers, can see quite a few examples of why they believe earlier series are better built than the later series, especially once 1980-81 rolled around. Evidenced by TO-3, metal cased outputs, shielding around the control pots and some sensitive circuit boards to reduce RFI noise, heavier control pots and Molex connected pre-driver / output circuit boards to facilitate future service.
Again, we have completely gone through this Pioneer SX-939 Stereo Receiver, as stated above and '
certified' it's ready to go!
This is only the second SX-939 we've had in almost 22 years of having the website.
Cosmetically the unit is in overall great condition for being ~45 years old. Only minor wear cosmetically. Unit looks good works great and sounds HUGE! Includes an 'e' copy / pdf download of the original Pioneer SX-939 owners / users / instruction manual, and brochure. Measures 20.5" wide x 16.5" deep x 6.75" high and weighs a
HEAVY 41
lbs unpacked. Includes our standard 90 day limited warranty!
PIONEER SX-939 STEREO RECEIVER
Cond. 8++

SOLD 9/7/19
SHIPPING TO CHRIS IN OHIO

(CONS. M.H.)
 

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

 

 




So, why do the older / 'vintage' receivers and amplifiers sound so much better (for music) than the much more modern and fancier, 'surround sound - '5.1', '7.1', '9 3/4.1' or '8.BR549' A/V receivers? (Part 2)

Cont from Part 1 of; “So, why do the older / 'vintage' receivers and amplifiers sound so much better (for music) than the much more modern and fancier, 'surround sound - 5.1', '7.1',
'9 3/4.1' or '8.BR549' A/V receivers?” (excerpts ‘paraphrased’ from …
So, just as importantly as the ‘technical aspects’ mentioned in “Part 1”, it’s ALL ABOUT THE MONEY, and we consumers want things as ‘cheaply as possible’, right…? Yes, we do, otherwise the market place wouldn’t be flooded with ‘cheeeeeeeeeeeeeeeeeeese’ from China (and from any of the other sources that can ‘make it as cheaply as possible). You say, “hold on a just gohl-darn minuite”, it’s the manufacturers fault, they’re the ones making things so ‘CHEAP’. NO, it’s not their fault. They are simply following consumer demands (who vote with their dollars, by continually spending as little as possible over the past generation++) and have no choice (at least in ‘mainstream goods’) but to produce and supply goods for as little ‘end user cost’ as possible,…”The Race to the Bottom”. Sure, we consumers give ‘lip service’ to terms like “high quality” and “good service”, but in the end, as a whole, we go for the cheapest options (one of the reasons service companies ‘outsource’ customer service to India, is that they can’t afford to pay ‘domestic labor rates’. Why not? Because we consumers want our phone / cable / insurance or whatever as ‘cheaply as possible, and we aren’t willing to pay for any better). Hey, I’ve been guilty of it a few times myself, but have learned the hard way (fortunately fairly early on)  to try and avoid that method of acquiring items and / or choosing service providers.
So, historically stereo manufacturers had to be concerned, primarily with ‘paying themselves’ in the end, when they designed / built / produced something. When mfgs start out to design an item for market, they are usually ‘backing into it’ from a projected retail / end user price point (that was not necessarily as applicable ‘back in the day’, which is how we ended up with ‘monster receivers’ such as the Marantz 2500 & 2600, Pioneer SX-1980, Sansui G-22,000 and G-33,000, Yamaha CR-3020 and a couple of others that escape me). There are many costs associated with bringing an item / model to market and getting it to the point where it can actually be purchased by an end user / consumer. These costs are similar no matter what the item, ie; stereo gear, clothes, tools, food, services, raw materials, or any item or ‘widget’. Some ‘added cost’ items have generally remained a constant as a percentage of the overall final price of an item, over the years, such as ‘raw materials’, payroll, capitol investments, packaging, transportation / shipping etc. However, in recent years, especially where ‘stereo receivers’ are concerned, manufacturers have been adding more and more features. Most of these “features” have little to do with improving the ‘REAL’ sound quality of the unit, and more to do with compatibility with extraneous aspects. We play DVD’s thru them that are encoded with ‘Dolby’, ‘THX’, ‘dbx’, 'DVD', ‘Lucas Sound’, ‘Blu-Ray’, etc. and inputs that mention things like “iPhone”, “Android”, “iPod”, “Apple”, etc. All of those things are ‘licensed’ from their respective trademark owners. Not to mention all of those manufacturers are constantly making changes (they tend to like to call them ‘upgrades’) to their products, which means that any mfg utilizing or including that ‘3rd party’ product as a feature in their product must now employ their engineers to modify their designs to ‘play well with others’. Those licenses cost money, and those costs take away from money that could be available to invest in the ‘sonic quality’ of the stereo unit.
Sonic quality is a sum of many parts, but a few are ‘discrete’ output transistors, instead of ‘chip’ outputs. ‘Metal-Cased / TO-3’ output transistors, instead of simply ‘epoxy-cased’ transistors. Larger power transformers, and larger storage capacitors to both make sure you have the available current to do the output transformers justice, and the ‘storage capacity’ to make sure you have enough power in reserve to produce deep, rich bass notes. Other aspects that add overall quality to a unit are the caliber of the switches, controls, contacts, semiconductors and components, shielding around sensitive circuits, internal wiring quality and connector / connections quality etc. Is the unit designed with ‘full size’ potentiometers, secured to the chassis with metal ‘shaft nuts’, or is it designed utilizing very ‘small body’ (read, “anemic”) potentiometers, with their control shafts simply protruding thru a hole in the front and secured only by their solder joints (which means that every time you touch / manipulate a control, you are ‘flexing / stressing’ the solder joints and circuit board). The same goes for the I/O jacks on the back panel. Throughout the unit, most
modern (most of what has been built in the past 25-30 or so years) electronics are built utilizing ‘SMD’ technology (look it up). While ‘SMD’ tech facilitates automated assembly processes (read, “robots”), keeps weight down (means lower handling and shipping costs), utilizes smaller individual components (again, ‘cheaper’ parts), SMD doesn’t generally lend to the improvement of ‘sonic qualities’. In-fact, it is probably THE BIGGEST CONTRIBUTOR to degraded, ‘analog’ audio quality. It’s great for things like calculators, computers, smart phones, appliances, automotive control devices etc (unless any of those units are expected to sound good). However, better ‘audio quality’ requires ‘better current’ (Amperes / Amps). Better current is generally best handled by traditional, ‘full size’ electronic components (the stuff designed, starting from about the 1920 thru the 1960’s, and generally peaking in designs released about 1977-79...at least as far as consumer hi-fi goes). Components such as ‘real transistors’ (or tubes if you’re so inclined), full size, electrolytic capacitors (bigger is generally better for storage, and that’s one of the main jobs of capacitors), ‘full size’ resistors to handle all that current without ‘melting down’ or going ‘up in smoke’, etc. The main reason that modern gear is able to attempt to accomplish the same tasks (and more) than vintage gear is that they convert the signal from analog to digital on the front end, and only at the ‘last minute’ convert it back to analog at the back end. That comes back to the generation plus old arguments of analog vs digital.
And the beat goes on…


 

 

 

         

NEW LISTING 8/27/19
(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED*
VINTAGE PIONEER STEREO RECEIVER
THE CLASSIC PIONEER SX-D7000 / SXD7000
BIG POWER @ 225 WATTS!
*

with "NON-SWITCHING" DC POWER AMP
'PSEUDO CLASS-A'

#...553S

  "
WORLD AC POWER"

Circa 1981-83

M.I.J.
for sale


ü  Our technician has completely gone through and 'Certified' this unit (with an exception*).

ü We have completely gone through this unit cleaning everything including all switches, controls and contacts (some are sealed).

ü Mains selector corrected from 110V to 120V AC

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet (when accessible)

ü We One issue we did not address due to 'practicality'. The tuner must 'warm up. due to a power regulator issue. It takes about 2-4 minutes for either AM or FM to work (due to a gradual voltage change / climb to operating level when first powered up. Also, due to this, if the tuner is selected and / or the speakers are engaged there will be an audible 'pop' at turn-on (if the unit has been off for a while). Once it's warmed up, the tuner works fine in all aspects. In our opinion, the resources to rectify the issue was not practical to expend)).
Other than that the FM performance is fine. Station memories are 'non-volatile' as well for either AM or FM when power off or in case of a lose of AC power.


ü Lamps / Bulbs replaced; FM indicator, Stereo indicator, & 'Phono-1' (3x 25-160)

ü Amplifier section had output bias adjusted to spec levels of ~56.0-58.9 mVDC on both amplifiers.

ü NOW both amplifiers have 'even' clipping on 'plus' and 'minus' rails.

ü DC offset adjusted to VERY LOW levels (0mVdc +/-5) on either amplifier.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 9 hours
.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.

This is a very elegant, versatile and great performing receiver. Again, as stated above, we have completely gone through this unit, and with the exception of the 'tuner issue' all works perfectly. All inputs tested and both side produces clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine. Following restoration procedures, the unit was ran continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours.

 
ü On our test bench, the internal amplifiers of this Pioneer SX-D7000 receiver, #...553S produced 33 Volts per channel @ 8 Ohms with 1Khz input for 136 Watts and 30 Volts per channel @ *4 Ohms with 1Khz input for *225 Watts via discrete,output transistors (4x 2SA1076 & 2x 2SC2526).
ü AC Idle current at 800mA
ü Bias adjusted to correct spec
ü DC offset output adjusted and measured down to < 0 (+/-5) mV DC either channel.
ü Floor noise measured @ >-60dBm AC either channel.
 

 One of the last of the classic silver face Pioneer receivers. Modernized by digital tuning and Blue fluorescent dual power meters. This is a 'POWER HOUSE' and can power medium to large systems. LOADED with inputs as well as listed below. As this is a 'Pseudo Class-A' amp (due to the Non-Switching design), it does run 'hot' (temperature wise) so needs plenty of ventalation. Should be set on 'risers' to increase clearance below, and not have anything sitting on top (Similar to other Pioneer SX-D"X"00, SX-3"X"00 series and their SA-X800 series).
Interestingly, this is the first of this "SX-D" series we've ever had that hasn't had 'dents' in the front, aluminum bezels. Looks fabulous!!!


Pioneer SX-D7000 Features include:
 

- Digital tuning with 6 AM & FM presets
- Auto / Manual tuning modes
- A, B & C speaker selector (two pair at a time)
- Classic Pioneer, Blazing Blue Fluorescent screen for digital station readouts, Tuning signal strength, Tuning, Station Presets and dual Power / Watt output meters
- Tuner Muting that works on not only FM, BUT AM AS WELL. (we've never seen this feature affect "AM" on any other tuner or receiver) (separate from 'Stereo / Mono' selector on Pre-amp)
-
Built-in Low / Subsonic filter to eliminate excess rumble from sources such as turntables and AC 'Hum' from connected devices
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.

 - Separate Bass and Treble that are both defeatable and have selectable frequency centers (Highs 2.5khz / 5khz, Lows 400hz / 200hz)
- Tone Defeat for purest signal path
 - 20 dB Audio muting
- FM De-Emphasis selectable
25µs or whatever is selected on 'rear panel' (on Front panel)
- FM De-Emphasis selectable 50µs / 70µs (on rear panel)
- Dual tape monitors (Tape Monitors can be used with Tape / Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Bi-Directional Tape 'Dubbing' capability

- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)
-  Dual Phono / Turntable inputs with Built-In Phono Pre-Amp
- MM / MC phono cartridge pre-amp selection (means "MC" 'Head-Amp' is built-in. That alone is worth a few hundred bucks if you need one)
- Dolby 'Adaptor' Loop can double as an additional input or as a signal processor loop for EQ, Dynamic Range Expanders, Reverbs, Delays, DBX units, etc.
 - Front panel light dimmer
- High quality de-tented volume control seated concentrically with the balance control

- Pre-out / Main-in loop (allows feed to an additional / larger power amp, or to 'direct feed' the power-amp in the receiver with another pre-amp or audio mixer)

- -20db instant audio muting
- AM stereo output via single RCA jack
- Selectable AM channel tuning steps (9khz or 10khz (for use either in North America, or the rest of the planet))
- ¼" stereo headphone jack
- True
"WORLD AC POWER" allows unit to be operated on 50 or 60 Hz AC and will select voltages from 110V, 120V, 220V and 240 Volts AC input. 
- 3 AC convenience outlets (1 switched 100W /  2 un-switched 200W)

Pioneer SX-D7000 Original Specs:

POWER / PRE AMP SPECIFICATIONS:
THD;
0.005% @ full rated power
Freq Response of power amp section; 3-450,000kHz @ 1W
Damping factor; >60 @ 8Ω full bandwidth
Hum and Noise of Power Amp; >115dB
Input Sensitivity (@ Power Amp in); 1V @ 50kΩ
Cont rated Power:
2x 120 Watts @ 8 Ohms / 20-20kHz

Hum and Noise; >100dB on AUX / Tape
Input Sensitivity AUX / Tape; 150mV @ 50kΩ
Record Out Levels; 150mV
Bass Control; ±8dB @ 100hz (selected for 200Hz) OR ±10dB @ 100hz (selected for 400Hz)
Treble Control; ±10dB @ 10khz (selected for 2.5kHz) OR ±8dB @ 10khz (selected for 5kHz)
Low (Subsonic) Filter;  -6dB @ 18Hz @ 6dB Oct
High Filter;  -10dB @ 10kHz @ 6dB Oct
"Loudness" Contour;  +6dB @ 100hz, +3dB @ 10khz (w/ volume set at -40dB)


TUNER SPECS FOR FM:
Tuning Range;
88-108MHz
Freq Response;
30-15kHz (limited by FCC)
S/N @ 85 dBf; > 78db Stereo
> 82db Mono
50dB Quieting Sensitivity;
Mono...15.7dBf (3.2 μV)
Stereo...34.2dBf (28.2
μV)
Capture Ratio; <1.0dB
Alternate Channel Selectivity @ 98mHz (±400kHz); >80dB
IF Rejection; >90dB
Image Rejection; >80dB
Spurious Noise Ratio; >80dB
THD @ 65dBf Mono @ 1kHz0.07%
THD @ 65dBf Stereo @ 1kHz0.1%
Stereo Separation; >50dB @ 1kHz
>35dB @ 30Hz-15kHz
AM Supression; 60dB

TUNER SPECS FOR AM:
Useable Sensitivity IHF; 300 uV/m with ferrite stick antenna
S/N @ 1 Mhz: > 45db
Image Response Ratio; >30dB
IF Response Ratio; >60dB
Selectivity; >30dB

PHONO SECTION SPECS:
Freq Response;
20-20kHz RIAA Standard Curve +/- 0.2dB

S/N on MM;
>86 dB
S/N on MC; >72 dB
Input Sensitivity MM;
2.5 mV @ 50kΩ
Input Sensitivity MC;
0.25mV @ 100Ω
 Overload limit;
200mV w/ 0.005% THD @ 1kHz

 

Unit sounds and looks great. The main, cosmetic issue is a 'ding' on the left edge of the left side panel (see photos). Oddly, this unit doesn't have any dents in the flanking bezels that we usually see, as the aluminum there is very thin. Overall, this is an impressive and VERY powerful unit. Includes an 'e' copy / pdf download of the original Pioneer SX-D7000 owners / users / instruction manual, and brochure.  Measures 22" wide x 7.75" tall x 18" deep and weighs HEAVY at 47 lbs unpacked. Includes a 30 day limited warranty (*due to tuner power supply issue, doesn't cover tuner function).
PIONEER SX-D7000
Cond. 8.5

$989.
(Cons. R.R.)

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

 

 

Jerry Gahagan, of Oak Tree Enterprises, LLC standing in front of one of a few 'batches' of speakers put together for an 'upper Mid-West' Micro-Brew chain.

 


Did you know?

MCS was marketed in the US, by JCPenney's in the 1970's and '80's and has generally proved to be solidly designed and built gear in the long run (not so much gear past early 1980's). Most MCS (Modular Component Systems) equipment was built by either Matsushita (parent company of Panasonic (founded 1918) and Technics (introduced 1965) or NEC (established 1898-99, originally known as Nippon Electric Company). Both VERY well respected, electronics industry giants. Most of the MCS stereo receivers and amplifiers prove to be fine performers once 'Certified' by a qualified technician. There are a few 'exceptions' and when we encounter one, they don't even make it to the bench, but then, most brands, including Pioneer, Marantz, Sansui, Kenwood, Sony & Yamaha made a handful of 'exceptionally cheaply designed and built' models that we won't bother to refurbish / restore. When I sold either Technics or Panasonic gear new, I knew there was a VERY low chance of that unit coming back with an issue, over many of the other brands I might have had at my disposal. Needless to say, I am a fan of most gear built by Technics / Panasonic and have seen enough of it to know that if I had to place a 'blind-bet' on an 'as-found' unit either being in 'functioning condition' or being close to it, gear built by Matsushita (NEC as well) will be a 'safe bet'.

 (Above text property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)


 

 

    


   

     

NEW ADDITION 8/27/19
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE STEREO RECEIVER
SANSUI 2000X STEREO RECEIVER
140 WATT RATED DYNAMIC POWER
 #...0852
Circa '73-76
"WORLD AC POWER" ™
MIJ

SOLD 9/11/19
SHIPPING TO LYN IN CALIFORNIA


ü Our technician has completely gone through and 'Certified' this unit.

ü Everything was cleaned inside and out including all contacts, switches, controls and I/O jacks.

ü Control Pot shafts re-sprung.

ü Internal and external fuses checked and replaced where necessary.

ü All 4 power transistors removed and tested for leakage.

ü Re-flowed multiple solder joints

ü We also aligned the tuner front end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years.

ü We re- aligned the tuner dial indicator for improved accuracy

ü All meter, dial, and FM stereo lamps replaced for trouble-free service (very difficult to do on this series of receiver). 6x #40 & 4x #25-130 bulbs / lamps.

ü Tuner string re-tensioned for improved flywheel 'grip'

ü Amplifier section had output bias and DC offset adjusted to spec levels

ü Repaired 'open' coil on tuning meter

ü Entire unit cleaned / detailed cosmetically inside and out, including a fresh coat of lemon oil rubbed into the Real Walnut wood veneer cabinet, while chassis was removed.

ü All inputs have been tested and both side produces clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.

ü Following our restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours and into a 4 Ohm Load! You will not be disappointed. Total restoration / ‘tech time’ investment ~13 hours.

ü On our test bench, both this unit's amplifiers, #...1204 produced peak power of 18 Volts per channel @ 8 Ohms for 40 Watts and 15 Volts @ 4 Ohms for 56 Watts per channel via discrete, TO-3, metal cased outputs with 1 kHz input. (4x Toshiba 2SC793, (same as Sanken 2SC1111)).
ü Idle current draw measured at 0.2A. Bias adjusted to spec of 20mA. (which by the way, once biased, brought the idle temperature of the heat-sink down from ~220F degrees to ~68°F)
ü DC offset adjusted to <15mVDC L & R unloaded and ZERO mV loaded (from the 75mVDC exhibited initially).
ü Floor noise measured at -60dBm AC w/ AUX shunted).
  ____________________________
  
This receiver is from what many consider to be one of Sansui's best eras. The Sansui 2000X stereo receiver. The "X" suffix designates upgraded F-6013 driver boards that are sought after by owners of "non-X" units as an aftermarket upgrade. We have had a few 'X000' series Sansui units and they are among some of the best sounding, 'vintage', 'main stream' amplifiers we have heard. Lots of headroom and punch! Similar in sound to many of the NAD amplifiers / receivers we sold back in the 80's. This one also is installed in the optional, REAL walnut wood veneer case that's in beautiful condition as well.

Sansui 2000X Features include:


§
  Weighted flywheel, 'slide rule' style analog tuning
§  Dual Tuning Capacitors. One for FM and one for AM. Allows for incredibly 'quiet' tuning
§  Speaker Damping Selector
§  A, B, A+B, Off, speaker positions
§  Separate Left and Right, Bass and Treble w/ 'concentric' controls
§  Hi-Filter for reducing tape hiss / electronic hiss & noise and record static
§  Built-in Subsonic Filter to eliminate excess rumble from sources such as turntables
§  Pre-Amp Out / Power-Amp In Loop (unique to the "X" version)
§  'TRUE' tape monitor featuring both RCA and DIN I/O's (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-Gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
§  Aux inputs (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-Gadget / MP3 / XM® / SIRUS®  etc.)
§  Tape B to Tape A Dubbing capability
§  Dual Phono / Turntable inputs with Built-In Phono Pre-Amps
§  "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
§  Stereo / Mono selector for Pre-Amp separate from the FM tuner selector
§  Pre-Amp Stereo / Mono selector
§  Stereo Reverse selector (great for troubleshooting speakers)
§  FM Muting separate from the Stereo / Mono selector
§  FM MPX filter (removes the 19kHz pilot signal from FM broadcasts)
§  Rear located MPX Separation & Level adjustments
§  FM Dist / Loc selector
§  Front mounted 1/4" stereo headphone jack
§  Tuning window features VU meter for tuning signal strength
§  Rear located speaker and main power protection fuses
§  Vertically finned heat sinks for very efficient cooling and long life
§  Built-In Ferrite 'Stick' AM antenna
§  True "WORLD AC POWER"™ allows unit to be operated on 50 or 60 Hz AC and will select voltages from 110v, 120v, 220v and 240 Volts AC input.
§  Dual AC convenience outlets on rear panel with 1 switched and 1 un-switched

Sansui 2000X SPECIFICATIONS:

POWER / PRE AMP SPECIFICATIONS:

Music Power: 140 Watts dynamic @ 4 Ohms
100 Watts dynamic @ 8 Ohms
Cont rated RMS Power: 2 x 52 Watts @ 4 Ohms, 20-20k & <0.8% THD
THD; 0.8% @ full rated power
IMD; 0.8% @ full rated power
Power Bandwidth (IHF); 20Hz-40kHz
Damping factor; 24 @ 8Ω & full bandwidth
Hum and Noise;  70dB on Phono w/ 2.5mV input and 80dB w/ 5.0mV input
Input Sensitivity AUX / Tape; 150mV @ 100kΩ
Bass Control;  ±12dB @ 50hz
Treble Control;  ±12dB @ 10khz
High Filter;  -10dB @ 10kHz
Low Filter;  -10dB @ 50Hz
"Loudness" Contour;  +8dB @ 50hz & +3dB @ 10kHz (volume control @ -30dB)

TUNER SPECS FOR FM:
Tuning Range;
88-108mHz
Freq Response; 30-15kHz
Capture Ratio; 1.0dB
S/N; > 60db Stereo
20dB Quieting Sensitivity Mono; 1.4μV
FM Alternate Channel Selectivity; > 40dB
Spurious Radiation; <34dB
Spurious Response Rejection; >90dB
Image Rejection Ratio; >90dB
THD 65dBf @ 1kHz, Mono;  <0.8%
Stereo Separation Ratio: >35dB @ 50Hz to 10kHz

TUNER SPECS FOR AM:
Tuning Range;
535-1605kHz
Image Frequency Rejection; >50dB @ 1kHz
IF Rejection; >80dB @ 1kHz
Useable Sensitivity; 100μV / m @ 1kHz with ferrite stick antenna
Selectivity; >20dB @ 1kHz

PHONO SECTION SPECS:
Freq Response;
20-20kHz

THD; 0.8% @ 200 mV @ 1kHz
Input Sensitivity; 2.5 mV @ 50kΩ on 'Phono-1' & 2.5 mV @ 100kΩ on 'Phono-2'
Max input; ~200 mV @ 50kΩ

Again, we have completely gone through this unit. This is the first Sansui 2000X we have refurbished in a few years. Brushed aluminum face and knobs in like NEW condition. Unit looks and sounds great! Originally 'Optional', but now included, Real Walnut wood, veneer case in decent condition, also in NEAR NEW condition with only the most minor of visible wear.
Again, these are known for their exceptional tuner quality on both AM and FM and their VERY PUNCHY sounding amplifiers. Very 'Musical' sounding stereo receiver. Measures 18" wide x 14" deep x 6.5" deep and weighs a whopping 34 lbs unpacked. Comes with standard 90 day limited warranty.
SANSUI 2000X STEREO RECEIVER
Cond. 8.5++

SOLD 9/11/19
SHIPPING TO LYN IN CALIFORNIA

(Cons. M.H.)


(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

    

          NEW LISTING 1/1/19
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE PANASONIC STEREO RECEIVER / 8-TRACK TAPE
PANASONIC RA-6800
AM/FM STEREO RECEIVER / 8-TRACK DECK

#...0512
Circa 1973-76
MIJ

for sale

  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. VERY time consuming to properly service this unit, especially the 8-track deck. Extensive cleaning of unit internally.



ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü  Entire transport was disassembled down to the chassis, and every mechanical part was cleaned of "varnished" lubes and re-lubed as well as the always at issue, Pinch Roller plunge assembly, re-lubed and reassembled (VERY DIFFICULT and TIME CONSUMING on this unit)

ü Cracked head mount repaired to allow accurate head azimuth and track alignment (8-track head mounting brackets are cracked about 80% of the time, but you won't know unless you disassemble to the point to allow a visual on it).

ü Main drive belt has been replaced with NEW for trouble free service (#42-480).

ü Replaced bad track indicator lamps, and checked the balance for function

ü Capstan flywheel removed, cleaned, burnished and re-lubed prior to re-install. Entire transport and mechanism has been cleaned, re-lubed and de-magnetized.

ü Program change mechanism and indicator contacts cleaned / burnished and re-lubed for trouble-free program changes. All original program indicator lamps now work fine.

ü Heads have been cleaned and de-magnetized and are in great shape.

ü Head azimuth & track cross-talk adjusted for optimum performance and the best high-frequency response (not normally expected from 8-track cartridge performance) utilizing RCA #356 and 8TSC-101, Aspen 'Deck Tester' and Audio-Tex 30-312 Test / Alignment tapes, a dual trace Oscilloscope and frequency counter.

ü Track alignment adjusted to eliminate 'cross-talk' between tracks and to ensure the best high-frequency response (not normally expected from 8-track cartridge performance) utilizing RCA #356 and 8TSC-101, Aspen 'Deck Tester' and Audio-Tex 30-312 Test / Alignment tapes, a dual trace Oscilloscope and frequency counter as well as our 'best' pre-recorded tapes.  Deck now has clear sounding highs even when using pre-recorded tapes.

ü Record signal path contacts cleaned and burnished for static-free performance

ü Linear Record switch cleaned so no 'Motor Boating' effect

 
ü Internal playback, meter and record level pots also adjusted w/ O-scope.

ü Following refurbishment, Speed checked with factory test tape to 98.5% accuracy! (meaning in this case, that our 1000Hz test tape plays back at 985Hz on our Freq Counter Meter)

ü Deck 'sonically' checked for WOW and Flutter with no appreciable issues

ü Record Meters adjusted for 'even' readout and performance

ü Floor noise tested @ -60dBm

ü Since we also burnished the program track light contacts, they all light and are responsive. Unit works and sounds GREAT!

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.



ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is above average for a 'stereo receiver' on this Panasonic RA-6800. 

ü All dial, indicator & meter lamps work or were replaced.

ü Stereo indicator lamp replaced (even though original was working)

ü We also checked the heat sink compound which should be good for another 30 years.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 15+ hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.
  
Mechanically the only issue worth mentioning is that that due to a cracked gear, common to about 50% of the 8-tracks out there, the tape counter was 'defeated'. About the only cosmetic issue worth mentioning is that I'm pretty sure the plexi dial window was less yellow when new.

ü On our test bench, each internal amplifier of this particular unit, #...0512, produced peak power of 15 Volts per channel for 28 Watts per channel @ 8 Ohm and ~12 Volts @ 4 Ohm for 36 Watts per channel @ 1khz. (Dual STK078).
ü AC Idle current at <.3A, & floor noise -60dBm.
ü DC offset checked to <30mVDC / channel (very good for a 'compact' unit).
  ____________________________
  

Wonderful condition, and REALLY GREAT SOUNDING, mid 70's silver face 'Combo' Receiver from Panasonic. It really is surprising in sonics, performance, feel and quality. Great performance for a 'small to mid-sized' 2-Channel audio system. This is the first 'compact' we have 'pass muster' in the past couple decades (I think the last one was about 1998 or 99 and shipped to Germany).
This is an INCREDIBLY ‘Musical’ sounding receiver. Lot's of surprising 'punch' and volume. It's also one of the best sounding 8-track decks we've auditioned (following restoration). Playback of 'quality' tapes is punch, balanced and bright (typically fairly un-common on 8-track decks). Recording is decent as well, but the playback quality is fabulous. Probably one of the top 2 or 3 decks we've ever had for playback sonics.
Yes, I know, it's a 'compact' and not a 'separate component', but it really is that nice!!! Enough power for up to 'medium-large' / 10" woofer speakers.

Panasonic RA-6800 Features:
  
Receiver:
-
Weighted flywheel analog slide rule tuning
- Separate Bass and Treble controls utilizing high quality de-tented pots
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- FM auto/muting and mono selection
- AFC (Auto Frequency Control) locks stations in for 'drift free' reception
- AM noise filter (located on rear panel)

- Dual Analog back lit meters for tape recording level and tuner signal strength
- Phono / Turntable input with Built-In Phono Pre-Amp for both Magnetic or Ceramic / Piezo cartridges
- Separate 'True' Tape Monitor with a DIN input as well as the standard RCA I/O's
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Microphone Input with 'mixing' function to add voice to music
(be careful with your speakers if using an 'open / live' mic with home-audio speakers)
- A, B, or A+B speaker selector
- Built-in, internal AM ferrite antenna
- Externally located Speaker / Amp protection fuses located on rear panel
- Dual 200 watt convenience AC outlets for a total of 300 Watts capacity

8-Track cartridge features:
- Stereo Playback and Recording 
- Back-lit, analog, Record Level VU level meters
- Separate L & R Input level controls or 'Auto-Level' selector
- LOCKING Fast Forward (very valuable, time / money saving feature if you have a 'media transfer business' or are transferring your own tapes to CD / computer files)
- Auto-Stop
for 'current track selection' for playback or recording (again, very valuable feature if you have a 'media transfer business' or are transferring your own tapes to CD / computer files)
- 'Pause' function
- Power assist Eject
- Single Track Repeat function

- 1/8" microphone inputs mounted on the front panel
- Microphone Input with 'mixing' function to add voice to music recordings on 8-Track
- 1/4" Stereo Headphone jack
- Rear mounted RCA I/O's

Again, we have done the previously stated refurbishment / restoration work (~15+ hours) on this unit to insure its performance, and it gets our full 'Certification'. All functions tested for perfect operation. This receiver has an awesome tuner. Overall, it is in great cosmetic condition! Looks and sounds great! Measures 19" wide x 7" tall x 16" deep and weighs 26 lbs unpacked. Includes our standard 90 day limited warranty.
Cond. 8.5
PANASONIC RA-6800 STEREO / 8-TRACK RECEIVER

$589.

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

 

 





           NEW LISTING 12/21/18

(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE PIONEER STEREO RECEIVER
PIONEER SX-580 / SX580
#...7704
Circa 1978-80

SOLD 8/30/19
SHIPPING TO NEBRASKA


ü  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Compromised AC line cord replaced

ü  Controls were 'flooded' w/ 'De-Ox-Id' and are quiet

ü Tuning flywheel 'froze' near the end of our refurb process, due to 'varnished lubes'. It could not be disassembled for cleaning / lubing. Fortunately we had another SX-580 for an original / OEM flywheel assembly. We disassembled it, cleaned and re-lubed it, then installed it into this one. Should be good for another 30-40 years now.

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü All dial & meter lamps checked as good, and as they are 'low current draw', should offer lots of trouble-free service. (by the way, we could have changed these, but they're the original, 'worth their weight in gold almost', AEL-029, Blue-Pioneer bulbs, still with most of their original, 'blue coating' intact) (if you want, we'll change them out prior to shipping, but we get to keep the originals)

ü We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours into a 4 Ohm load.

ü All inputs tested and both side produces clean and even sine waves into static 8 & 4 Ohm, 'brick wall' loads! No power supply hum of any kind. It's dead silent! All functions test fine. Following restoration procedures, the unit was ran continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours. All functions test perfectly. This one is also cosmetically "Like New" in every respect! No issues anywhere.
  
ü On our test bench, each internal amplifier of this particular unit, #...7704 produced peak power of 15.5 Volts at 8 Ohms per channel for 30 Watts / channel and 12.8 Volts at 4 Ohms per channel for 40 Watts / channel via STK-0029 type, output power packs. 
ü DC offset output adjusted to: <3mV on each side.
ü AC draw at idle 0.30A
  
___________________________ 
 
Great entry level model from the classic SX-x80 series. The Pioneer SX-580 stereo receiver. Great for small system in dorm, office, shop, bedroom or anywhere you don't have a lot of components to attach and your speakers have 10" or smaller woofers, but still desire the look and performance of a classic.
Pioneer SX-580
Features include:
  
 
-
Analog Weighted Flywheel tuning on full-width back-lit slide rule tuning scale
- A & B speaker selector
- Separate Bass and Treble controls utilizing super quality de-tented pots
- Phono input
- Tape monitor
(Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Aux input
(can be used with Cassette Tape Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®
- Dual analog VU Power Level meters
- Analog VU meter for Signal Strength and Tuning
- FM Muting / Stereo / Mono selector
- Built-in Loudness control
- 1/4" Stereo headphone jack
- Built-in AM ferrite "Stick" antenna
- Rear panel features selectable FM De-Emphasis at 25 or 75 micro-seconds
- Dual AC convenience outlets (1 switched @ 50 Watts / 1 un-switched @ 100 Watts capacity)

  
 
This receiver features a very nice design feature in that the output devices are mounted on the bottom side of the heat sinks for less dust build-up which will allow them to run much cooler for a longer life and tighter sound.
  Again, we have completely gone through this unit cleaning everything including all switches, controls and contacts as well as replacing all dial lamps for trouble free service. All functions test fine. Unit looks decent with a few minor 'battle scars' to the wood grained, vinyl wrapped case (see photos above). Sounds and performs great!
 
Measures 17" wide x 12.5" deep x 6" tall and weighs 19 lbs unpacked. Includes our standard 90 day limited warranty.
PIONEER SX-580
COND. 8.5

SOLD 8/30/19
SHIPPING TO NEBRASKA

(Cons. M.H.)


(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 
 

Did you know?
While the company 'Pioneer' was officially established in 1961, the founder was actually developing speakers as early as 1937. In 1962 Pioneer marketed the worlds first 'separate component' stereo system for the home, and in 1975, the worlds first 'component system' for the car. In 1984 they introduced the first CD player for the automotive use (and I was selling it then). Pioneer had many other 'firsts' and continue to be a major 'player' in consumer, professional and industrial electronics.

 

 

 

Yamaha_R-700_Stereo_Receiver_web-b.jpg   

  Yamana_R-700_Receiver_Collage.jpg


       NEW LISTING 1/7/17
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED / WARRANTED
VINTAGE
YAMAHA R-700 STEREO RECEIVER
#...0340
Circa '81-'83
MIJ

for sale


Our technician has completely gone through and 'Certified' this unit.
Everything was cleaned inside and out including all contacts, switches and controls. We tested all circuits associated with Yamaha IG04540 'voltage amplifier' pack as well as select resistors and checked for 'leaky' capacitors in the drive circuit. DC offset and bias PC mounted pots cleaned and current adjusted to within spec. Tuner 'memory capacitor' replaced. Entire unit cleaned / detailed cosmetically inside and out. All inputs tested and both side produces clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine. Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a 4 Ohm load with "Loudness" on and both Tone Controls at 10 for 48 hours and into a 4 Ohm Load!

   

ü  On our test bench, each internal amplifier of this particular unit, #...0304, produced peak power of 25 Volts per channel for 78 Watts per channel at 8 Ohms and 21 Volts at 4 Ohms for 110 Watts per channel via dual Yamaha IG 04570 power pack output devices.
ü AC idle current draw measured at 0.4A.
ü Floor Noise Level tested at <1mVAC.
____________________________

Great Yamaha R-700 receiver designed in the tradition of the classic analog models, but with the convenience of a digital tuner. Very nice looking unit. Classic Yamaha "Satin" finish aluminum face and matching knobs.
Yamaha R-700 Features include:
  
- Digital tuning ('Auto' scanning only. No 'Manual' on the R-700)
- 5 AM & 5 FM tuner presets

- A, B and A+B speaker selector
- Separate Bass and Treble with high quality de-tented controls
- Record Out selector with bi-directional tape dubbing controls.
(Separate "Record Out" allows recording from one source while you listen to another. ALSO, it is the way you can utilize external EQ's, and Signal Processors with many Yamaha Receivers, as their 'Tape' buttons typically 'cancel' out the 'Input / Source' selected)
- Dual tape deck monitors (Tape Monitors can be used with Video / CD / DVD / VCR / DAT / iPod / MP3 / XM / SIRUS CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Phono / Turntable input with built-in phono pre-amp
- AUX Input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)
- Yamaha's exclusive Variable "Loudness" control
- Variable Spatial Expander built-in
- Hi filter for reducing tape hiss / electronic hiss & noise- and record static
- Stereo / Mono selector for entire 'Pre-Amp'
- FM muting / FM 'Stereo / Mono' function
- Auto 'Local / DX' selector
- Digital indicators for Station frequency, DX / Local mode, Stereo and Station Lock as well as an LED signal strength meter
- Triple AC convenience outlets located on the rear panel (1 switched @ 200 Watts and 2 un-switched @ 200 Watts for a total capacity of 400 Watts)

   
 Yamaha R-700 Original Specifications:

 
"The Yamaha R-700 has a continuous / RMS power output of 50 Watts per channel min. @ 8 Ohms from 20 hertz to 20,000 hertz with no more than 0.01% THD (measured utilizing AUX input)"
  
POWER / PRE AMP SPECIFICATIONS:

Freq Response / Bandwidth of power amp section;
@ 25 Watts / 8-Ω  5-40kHz
THD utilizing AUX;
0.02% @ 25 Watts 5-40kHz
Dynamic Headroom; 2.5dB! @ 8-Ω
Damping factor; >40 @ 8-Ω full bandwidth
Rated Power; 50 Wpc @ 8 Ohms @ 1kHz
Signal / Noise ratio;  100dB @ AUX / Tape
85dB @ Phono MM
Input Sensitivity AUX / Tape; 17mV
Tape Output level;
  120mV / 470-Ω
Bass Control Characteristics;  ±10dB @ 50Hz
Treble Control Characteristics;  ±10dB @ 10kHz (manual states at 20kHz, but that has to be a 'mis-print. Just FYI per Jerry at www.oaktreevintage.com .)
Treble Filter;  6dB / Oct @ 8kHz
Low Filter;  'Automatic' 12dB /Oct @ 10Hz
"Loudness" Contour;  Maximum -20dB @ 1kHz
  
TUNER SPECS FOR FM;
 
Tuning Range;
87.6-108 MHz
Freq Response;
30-15kHz ±0.5 dB
S/N; > 80db Stereo
S/N; > 84db Mono
50 dB Quieting Sensitivity:
Mono (DX) 3.2μV (15.3 dBf)
Stereo (DX) 25 μV (33.3 dBf)
Useable Mono Sensitivity (98 MHz, 30 dB Quieting);
2.5 μV (300 Ohms) 13.2 dBf
1.25 μV (75 Ohms) 13.2 dBf
Capture Ratio; 2.2dB DX, 1.5dB Loc
FM Selectivity; 68 dB
Spurious Response Ratio; 100 dB
IF Response Ratio; 100 dB
AM Suppression Ratio; 65 dB
FM separation;  50dB @ 1kHz
Auto DX Threshold; 30 μV / 34.8dB
  
TUNER SPECS FOR AM;
Tuning Range;
525-1605kHz
S/N; > 50db
Useable Sensitivity; 200μV / m with loop antenna
Selectivity; 30dB
Spurious Response Ratio; 50dB
Image Response Ratio; 40dB
  
PHONO SECTION SPECS;
Freq Response;
20-20kHz

S/N @ 5mV / Input shorted;
85dB with MM cart.
Input Sensitivity; 2.5 mV w/ MM
Overload limit; 250 mV
  

Again, as stated before, we have completely gone through this Yamaha R-700, Stereo Receiver cleaning and testing all and it gets our full 'Certification' . All functions test fine, with the exception of the tuning 'memory presets'. They can be a bit 'finicky' on this unit. Most of the time they work fine, but occasionally when you press one, you will get the station a few '10ths' off, ex: if you store "91.50", you might get "91.30" next time you go to that preset. If you press it once or twice more, it usually goes to the correct "91.50". Installing a new 'memory cap / battery' did not address the issue. Not likely an issue for most folks, but it's there
Dark Rosewood grained vinyl covered case in great shape as is the brushed aluminum face and matte finish knobs. This receiver looks near NEW, works and sounds great!

Comes with an 'e' copy pdf, download of the Yamaha R-700 users / owners manual. Unit measures 19" wide x 4.75" tall x 13.25" deep and weighs 20 lbs unpacked. Includes our standard 90 day limited warranty.
 YAMAHA R-700 STEREO RECEIVER
 Cond. 9

$329.00

- 
(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

Did you know?
It would be hard to name a category of 'musical instruments', 'audio equipment', 'motorized vehicles', or 'sporting equipment' that Yamaha does not have a 'hand in' with 'branded models'. Most folks do not realize this, but Yamaha is one of the oldest companies in existence, certainly when it comes to music gear and was actually established in 1887 and was incorporated on October 12, 1897! The company's origins as a musical instrument manufacturer is still reflected today in the group's logo—a trio of interlocking tuning forks. Yamaha has grown to become the world's largest manufacturer of musical instruments. I have worked for Yamaha dealers over the years, in both the 'consumer' level and 'pro-audio' / 'MI' level. Their gear was 'spec'd' more often in the military contracts we received, than any other brand. I knew when I sold a Yamaha unit, there was little chance of an 'issue after the sale'. Yamaha products are known as having about the best 'resale value' of any brand, regardless of the product class.

 

 


A COUPLE OF 'AS-IS' RECEIVERS.
NORMALLY WE DON'T OFFER UP 'AS-IS' UNITS, BUT WE HAVE LIMITED TECH TIME, AND AS THESE ARE A COUPLE OF FAIRLY 'HIGH PROFILE' / SOUGHT-AFTER RECEIVERS...
 

         

NEW LISTING 7/23/19
(Click on above thumbnails to enlarge photos)
VINTAGE & BEAUTIFUL FISHER STEREO RECEIVER
THE CLASSIC FISHER 800-T (SAME AS 500-T EXCEPT ALSO HAS AM)
Circa 1969
#...2638
MADE IN USA

for sale

AS-IS - "AUTOSCAN" FUNCTION DOES NOT SEEM TO WORK

ü Our technician has gone through this unit to a point

ü All Dial, Meter, Stereo Indicator and 'Beacon' lamps work currently

ü Noisy pots / controls cleaned to facilitate service

ü Electrolytic power supply filter capacitors tested for leakage

ü All question-able and common 'stress point' solder joints re-flowed

ü All 4 power transistors removed, tested for leakage

ü Bias current adjusted to correct levels.

ü DC offset adjusted to super low levels.

ü We also aligned the tuner 'front-end' for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM reception WAY above average, FM reception incredible, PUNCHY, with GREAT SEPARATION and IMPECCABLY CLEAN!!!

ü Tuner 'Station Indicator / pointer' should be aligned.

ü Controls and pots should be further cleaned

ü As a 'side note', ALL the original, brushed, anodized, aluminum 'Knob Brites' intact!

ü Entire unit cleaned cosmetically inside and out (but not detailed). Receiver looks good

ü All inputs tested and both sides produce clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.

ü Following basic bench check procedures, the unit was run continuously at medium volume, as all our amplifiers / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours and into a 4 Ohm Load!

ü On our test bench, the internal amplifiers of this Fisher 800T receiver, #...2638 produced 21 Volts per channel @ 8 Ohms with 1Khz input for 55 Watts and 14 Volts per channel @ 4 Ohms with 1Khz input for 49 Watts via discrete, TO-3, metal cased, Motorola outputs (2x Motorola TR1038-5 & 2x TR1039-5).
ü AC Idle current at 300mA
ü Bias adjusted to correct spec
ü DC offset output adjusted down to 1.5mV DC either channel.
ü Floor noise @ < 2.4mVAC either channel.
   ____________________________


This is a very sought after model, we just don't have the tech resources to pursue the 'Auto-Scan' function, thus didn't invest more time into it on much of it's other aspects as well (however, even if it was working, it's a fairly 'useless' feature (we have a 450T that it does work on. Also, there are Youtube videos that demonstrate it's limited effectiveness even when functioning correctly).
This is the first Fisher 800T we've had in almost 24 years of having the website. We've had it here a few years, but just now decided to sell it with the 'Auto-Scan' not appearing to work correctly.
Cosmetically the unit is in overall great condition for being ~45 years old. Again, we really have only done a cursory cosmetic service. Unit looks good works great and sounds great! Includes an 'e' copy / pdf download of the original Fisher 500T (again, same unit without AM) owners / users / instruction manual, and brochure. Measures 17.5" wide x 14" deep x 6" high and weighs a
HEAVY 35
lbs unpacked.
Fisher 800T STEREO RECEIVER
Cosm Cond. 8+
$850. As-Is
(CONS. R.R.)

(Any additional service / restoration work may be undertaken at any time and will be reflected in an adjustment in price.)

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 



 

    

NEW LISTING 7/23/19
(Click on above thumbnails to enlarge photos)
VINTAGE FISHER STEREO RECEIVER
THE CLASSIC FISHER 450-T
W/ "AUTOSCAN ELECTRONIC TUNING"

Circa 1969
#...3328
MADE IN USA

for sale

AS-IS - One channel not producing as much "Bass / Fullness of tone" as the other channel.

ü Our technician has gone through this unit to a point

ü Most Dial, Meter, Stereo Indicator lamps work currently (one dial lamp out)

ü Noisy pots / controls cleaned to facilitate service

ü Electrolytic power supply filter capacitors tested for leakage

ü A number of electrolytic capacitors changed in the 'audio path', but that made no difference in the tone (no, we didn't do all of them)

ü All 4 power transistors removed, tested for leakage (we actually switched sides to see if that made a difference in tone)

ü DC offset adjusted to low levels.

ü We also aligned the tuner 'front-end' for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM reception WAY above average, FM reception incredible, PUNCHY, with GREAT SEPARATION and IMPECCABLY CLEAN!!!

ü Entire unit cleaned cosmetically inside and out (but not detailed). Receiver looks good

ü One channel not producing as much "Bass / Fullness of tone" as the other channel. On the scope, there's noise on the left channel at around 300Hz, which is likely related to the lack of bass.?...

ü Missing one rubber foot (we didn't pursue due to diminished tone)

ü As a 'side note', ALL the original, brushed, anodized, aluminum 'Knob Brites' intact!

ü All inputs tested and both sides produce clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.

ü Following basic bench check procedures, the unit was run continuously at medium volume, as all our amplifiers / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours and into a 4 Ohm Load!

ü On our test bench, the internal amplifiers of this Fisher 450T receiver, #...3328 produced 21 Volts per channel @ 8 Ohms with 1Khz input for 55 Watts and 15 Volts per channel @ 4 Ohms with 1Khz input for 56 Watts via discrete, TO-3, metal cased, Motorola outputs (2x Motorola 1060 & 2x 2060).
ü AC Idle current at 220 mA
ü Bias adjusted to correct speck
ü DC offset output adjusted down to <10 mV DC either channel.
ü Floor noise @ < 0.1mVAC either channel.
   ____________________________


This is a very sought after model, but unfortunately it is lacking 'low end' response on one side. We pursued it for a few hours, but had 'bigger fish to fry' and we just don't have the tech resources to pursue it further (You can actually get both channels to sound similar by increasing the bass on one, and decreasing the bass on the other (it has separate L & R Tone controls) ) .
The 'Auto-Scan' function does work.

This is the first Fisher 450T we've had in almost 24 years of having the website. We've had it here a few years, but just now decided to sell it with one channel lacking as much bass as the other.
Cosmetically the unit is in overall great condition for being ~45 years old. Again, we really have only done a cursory cosmetic service. Unit looks good works great and sounds great! Includes an 'e' copy / pdf download of the original Fisher 450 owners / users / instruction manual. Measures 15.5" wide x 14.25" deep x 4.5" high and weighs
25 lbs unpacked.
Fisher 450t STEREO RECEIVER
Cosm Cond. 8+
$399. As-Is
(CONS. R.R.)

(Any additional service / restoration work may be undertaken at any time and will be reflected in an adjustment in price.)

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

 



Did you know?
A SUPER LOW DISTORTION RATING COULD LIKELY BE A BAD THING!...
THD
(Total Harmonic Distortion) – THD is a measure of the how much a given audio device may distort a signal through the inevitable introduction of added harmonics or overtones. These figures are usually given as percentages. THD figures below approximately 1% are inaudible to most people (although market promotion efficiencies have 'brain-washed' much of the 'audio-public' into weighting low THD with almost 'holy grail' importance. I remember some manufacturers touting numbers as low as <0.003% in the early Eighties).  Low THD is not always an indication of a high quality amplifier. In fact, it is / was more commonly just the opposite. Some of the 'highest end' (read REALLY expensive) and certainly best sounding units will have distortions somewhere between .1% & 1%.
Low THD is only a simple 'bi-product' of 2 aspects. The first was an inordinate and increasing amount of 'global / negative feedback' built into amplifiers primarily to suppress distortion. This practice started to occur in the late 1970's and certainly was in 'full force' past the early 1980's for most 'main stream' consumer-grade audio amplifiers. Unfortunately this also 'suppressed' tone and 'punch' (musicality) but it made the numbers look good to the 'spoon fed' consumer (kind of like overly high speaker wattage numbers, and sorry if you're in that group and, most folks were so you're not alone). Secondly manufacturers were moving away from 'discrete-transistor' output designs to more 'monolithic' 'power-pack' output designs. While these designs reduced power supply requirements, thus reducing parts costs and weight (also translates to lower prices due to savings on freight from Asia) they generally sounded anywhere from somewhat 'anemic' compared with the designs from a few years previous, to completely 'gutless' and 'un-musical'. But, hey,… they had very low distortion figures….Can anyone say 'threw the baby out with the bath water'?

Excerpts of the above text from the website of one of the best Car Audio sites and stores in the world, 'Car-Fi' www.car-fi.com .

  

 


 



So, why do the older / 'vintage' receivers and amplifiers sound so much better (for music) than the much more modern and fancier, 'surround sound - '5.1', '7.1', '9 3/4.1' or '8.BR549' A/V receivers? (PART 1)


 
 Mostly due to Amplifier design and 'Amplification Classes' - All sound is a sinusoidal waveform. It has alternating peaks and valleys. The center point of each wave is the zero, or switching point that separates the positive (top) from the negative (bottom) portion of each wave. When a amplifier operates in 'Class A' , the output tubes or transistors amplify the entire waveform without splitting it into positive and negative halves. In 'Class AB', (used in the majority of classic receiver / amplifier designs), the signal is split into two halves, positive and negative, and each half is sent to a tube or transistor circuit for amplification. Both sides work in tandem, and the two halves are recombined at the output section to reconstruct the whole signal. This technique increases the amount of power that can be applied, but increases distortion.
In many 'modern' A/V and subwoofer amps, 'Class-D' is the dominant design method. Class D operation is essentially a rapidly switching power amplifier. Here the output devices are rapidly switched on and off at least twice for each cycle. Theoretically, since the output devices are either completely on or completely off they do not dissipate any power (heat), greatly increasing efficiency and lowering manufacturing cost thru lesser parts and lighter freight weight. Not musically the best sounding design for listening to standard, 2-channel music (Radio, Vinyl, CD'S, DAT, Tape (not 'crappy' compressed, MP3 formatted files), but popular for 'A/V-Surround-Sound' systems for reproducing 'movie sound tracks' (not too difficult to do from a 'sonic quality standpoint') where slightly elevated levels of distortion are tolerated and for subwoofer use where maximum power is necessary, and slightly elevated levels of distortion are also easily tolerated...Cont in Part 2 (also on this page)

Excerpts of the above text from the website of one of the best Car Audio sites and stores in the world, 'Car-Fi' www.car-fi.com .

  

- - -

 

 



Did you know?

What is the difference between a ‘Tuner’ and a ‘Receiver'?

A ‘Tuner’ is the component or aspect of an audio system that receives or ‘Tunes-In’ Radio Stations.
A 2-channel, stereo ‘Receiver’ is really 3 units in one!
It’s a ‘Tuner’ for receiving radio stations. It’s a ‘Pre-Amp / Control-Amp’ for source / input selection & tone / audio signal modification (with likely the phono 'pre-amp / head-amp' built-in). Lastly it’s a ‘Power Amplifier’ to energize your speakers. It's essentially the 'heart' of most audio / stereo systems.
Some manufacturers would silk-screen 'Tuner-Amplifier' on the front of their receivers, but that was / is simply 'marketing' to make it sound as if it's something more complicated. It's still a 'receiver'. Just FYI.

 

 

What is a 'Receiver' and how is it different than a 'Tuner' or an 'Amp'?
The term 'Receiver' refers to a combined unit consisting of at least 3 aspects incorporated into one. The 3 basic units are the AM/FM 'Tuner' or radio, a 'Pre-Amplifier' / 'Control-Amp' and a 'Power-Amplifier' all combined in one 'box'. Originally the general consensus was that 'receivers' did not perform as well as 'separates' and were sonically inferior. While this may have been the case early on, as in the

 

late 1950's to early '60's, technology improved quickly and by the mid-late 60's the arguments for separates over receivers for most 'mid-level' consumer Hi-Fi applications were generally without merit. For 95% of home-audio listeners, a receiver will be more than ample.

 




 

Click here for our Restoration Procedures



 
- -  

 

Jerry Gahagan of OakTreeVintage
Taken in portion of Speaker Audition Room
Vintage Home Audio Speakers from the late 1960's into the 1980's

 

 

-
SOLD ITEMS BELOW

 



 

 
 


CLICK HERE TO SEE OUR ARCHIVE OF
 SOLD RECEIVERS.
 

WE WILL LIKELY GET MORE OF THEM AGAIN!!!

    

        NEW LISTING 9/21/16

 (Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE
PIONEER STEREO RECEIVER
PIONEER SX-1500T STEREO RADIO / RECEIVER 
#...6766
CIRCA 1968-70

MIJ!

SOLD 6/6/19
SHIPPING TO MICHAEL IN CALIFORNIA

We have completely gone through this cleaning inside and out including all contacts, switches and controls. All indicator lamps and dial / meter lamps replaced with new units, for trouble-free service. We also aligned the tuner for optimum performance on both AM and FM. All functions tested for perfect operation. All inputs tested and both sides produce clean and even sine waves! No power supply hum of any kind. It's dead silent! All functions tested for perfect operation.

Very impressive early Pioneer unit from their 1st series of "Solid State" Stereo Receivers. This was one of the most likely Pioneer receiver to come back with Vietnam GI's. First one of these we've had in 19 years to make it 'all the way through' our refurb / restoration, and was a 'good enough' likely candidate to begin with. Loaded with very useable features and looks great! The tuner on this one is VERY strong on both AM an FM, with AM reception that we would describe as 'AMAZING' (yes, I know, most folks couldn't give a hoot about AM, but a few of us here, including me do, and were very impressed by it's AM performance).

ü  On our test bench, the internal amplifiers of this Pioneer SX-1500T receiver #...6766 produced 19.5+ Volts per channel @ 8 Ohms with 1KHz input for 47+ Watts and 15+ Volts per channel @ 4 Ohms with 1KHz input for 57+ Watts via discrete, TO3, metal cased output devices (4x Toshiba 2SC793 output transistors).
 AC Idle current at .2A. DC offset output <11mVDC either channel. Floor noise tested a 1.0mVAC.

   ____________________________

Pioneer SX-1500T Features include:

- Weighted flywheel analog slide rule tuning
- Separate L/R- Front/Rear Bass and Treble Controls
- Built-in Hi and Sub filters for reducing 19kHz pilot tone and 38kHz Harmonic in FM broadcasts, Tape Hiss and the Sub filter for reducing turntable rumble 
 - FM muting, separate from FM stereo selector
- Selectable FM Modes for Stereo or Mono
- AFC (Automatic Frequency Control) for improved FM reception
- Stereo Mode selector for entire Pre-Amp section selects; Mono, Right channel or Left channel input only & for Standard Stereo
- Analog lit, '
d'Arsonval' meters for tuning/ signal strength
-  AUX Input (may also be used for Video / CD / DVD / VCR / iPod / DAT / MP3 / XM / SIRIUS etc.)

- Tape Monitor (Tape Monitors can be used with Video / CD / DVD / VCR / DAT / iPod / MP3 / XM / SIRIUS CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc) Dubbing can be used with CDR (CD recorders) units)
- Additional Direct Tape Head input (for older Reel Decks that did not have a built-in pre-amp)
- Selectable Tape Speed EQ input for either 7.5 ips or 3.75 ips. (used for older Reel Decks that did not have speed compensating EQ or Pre-Amps built-in)
- Dual Phono inputs with input 1 being selectable for either standard magnetic or can also be used with older Ceramic cartridge turntables. Input 2 is strictly for modern / standard magnetic cartridges
- Built-in AM ferrite antenna
- Speaker On / Off selector
- Rear mounted, Separation control for fine tuning FM MPX
- 2 convenience AC outlets with 1 being switched
- True “
WORLD AC POWER"
as it will work on both 50 or 60 Hz AC and voltages from 110-240 Volts AC.

Original Pioneer SX-1500T Specs:
"The Pioneer SX-1500T has a RMS power output of 55 Watts per channel min. @ 8 Ohms from 20 hertz to 70,000 hertz with no more than 0.500% THD (measured utilizing AUX input), with a "Music Power Output" of 140Wpc @ 8 Ohms and 170Wpc @ 4 Ohms"
 
POWER / PRE AMP SPECIFICATIONS:

THD:
0.500% @ full rated power
Freq Response of power amp section: @ full rated power 20-70kHz
Power Bandwidth w/ all channels driven: 15-70,000Hz ±0dB
Damping factor:
25 @ 8Ω / 1kHz
Input Sensitivity / Impedance for AUX: 100mV / 100k Ohms @ 1kHz
Input Sensitivity / Impedance for Tape Monitor: 200mV / 100k Ohms @ 1kHz
Input Sensitivity / Impedance for Tape 'HEAD': 1.5mV / 120k Ohms @ 1kHz

TUNER SPECS FOR FM:
Freq Response:
30-15kHz (limited by FCC regulations)
FM TUNING RANGE: 87-108MHz
S/N: 
>65db Stereo
Useable Mono RF Sensitivity:
1.7 μV
Capture Ratio:
1dB
Image Rejection: 76dB @ 98MHz
Stereo Channel Separation @ 1kHz: 
37dB

TUNER SPECS FOR AM:
AM TUNING RANGE: 525-1605kHz
IHF Sensitivity:
20 μV
Image Rejection: 60dB @ 1MHz

PHONO SECTION SPECS:
Freq Response:
20-20kHz
S/N:
80 dB
Input Sensitivity 'MAGNETIC':
2.4 mV @ 50kΩ & @ 1kHz
Input Sensitivity 'CERAMIC':
51mV @ 90kΩ & @ 1kHz


Again, receiver has had complete service as stated earlier, and all functions tested. One note about this unit, as well as some of the 'Vietnam' era units is that the RCA I/O's on the rear panel are located fairly close together, and you'll need to utilize fairly 'normal' jacketed RCA connectors / plugs, and not some of the 'modern / FAT' jacketed versions as there's not enough clearance for them. Unit looks near NEW and sounds great. Face and all original knobs intact and look great as does the wood grain, case! Includes a pdf, 'e' copy, download of the Pioneer SX-1500T owners / users / instruction manual. Also comes with a pair of those, "worth their weight in gold" Pioneer speaker plugs. Measures 16.5" wide x 13.75" deep x 5.5" tall and weighs 25 lbs unpacked. Comes with our standard 90 day limited warranty.
PIONEER SX-1500T
Cond. 8.5+

(Cons. R.R.)

SOLD 6/6/19
SHIPPING TO MICHAEL IN CALIFORNIA

(Above text property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 

 

 

    

    NEW ADDITION 8/16/18
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE STEREO RECEIVER
LAFAYETTE LR-5555
AM/FM STEREO RADIO / RECEIVER
#...
0371
Circa 1977-81
MIJ!
SOLD 7/25/19
SHIPPING TO WASHINGTON

ü  Our technician has completely gone through and 'Certified' this unit. Everything was cleaned inside and out including all switches, controls and contacts.

ü
Internal fuses checked for correct value / function and replaced where necessary.  

ü Controls tightened to chassis.

ü
All dial / meter LED illumination lamps functioning.

ü
We also aligned the tuner front-end, FM MPX and dial alignment for optimum performance as older tuner components will have 'drifted' over the years.  INCREDIBLE TUNER! Unfortunately the AM is no longer functional on this unit, and the resources to rectify that was not monetarily practical.
FM reception incredible,
PUNCHY and MUSICAL and IMPECCABLY CLEAN!!!

ü
Following above procedures, all functions tested for perfect operation and unit was cosmetically detailed inside and out.  

ü
All inputs tested and both sides produce clean and even sine waves into static 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions tested for perfect operation.  

ü Following restoration procedures, the unit was ran continuously at medium volume, as all our amplifier / receivers are, into a 4 Ohm load with "Loudness" on and both Tone Controls at 10 for 12 hours.
  
On our test bench, each internal amplifier of this particular unit, #...0371, produced peak power of 23 Volts per channel for 66 Watts per channel @ 8 Ohm and 20 Volts @ 4 Ohm for 100 Watts per channel at 1kHz. AC Idle current at .5A. DC offset set down to <23VDC / Channel & floor noise -60dBm.
____________________________
  

Great looking silver face receiver from Lafayette. Great performance for a 'mid-sized', 2-Channel audio system. This is an INCREDIBLEY ‘Musical’ sounding receiver. The tone / pre-amp section sounds great, even with only the FM tuner as a source!

 
Lafayette LR-5555 Features:
  
- Weighted flywheel analog slide rule tuning
- A, B, C A+B or A+C speaker selector
- 3-Band EQ with Separate Bass, Mid and Treble controls utilizing high quality de-tented pots as does the 'Volume' control
- 'Tone Bypass / Flat' selector to bypass tone circuit for purest tone path

- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- FM Muting separate from 'Stereo / Mono' switch
- Stereo / Mono selector for entire Pre-Amp (not just the FM tuner)

- Hi filter for reducing tape hiss / electronic hiss & noise and record static

- Analog meter for signal strength (however, the 'Signal Strength' meter is always 'Maxed' on this unit and was not practical to address.
Analog 'Tuning' center meter
- Phono / Turntable input with Built-In Phono Pre-Amp
- Phono selector for either 'magnetic' or 'Crystal / Piezo' cartridges

- Dual, 'True' Tape Monitors with standard RCA I/O's
(Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- 1/4" front mounted, Microphone input jack w/ Level Control (BE CAREFUL WITH YOUR 'HOME AUDIO GRADE' SPEAKERS DOING THIS!!!)

- Built-in AM ferrite 'stick' antenna
- Dual Convenience AC outlets. 1x Un-switched rated to 200 Watts and 1x 'Switched' at 100Watts

Again, we have done the previously stated refurbishment / restoration work on this unit to insure its performance, and it gets our full 'Certification'. As mentioned earlier, with the exception of the AM and the 'Signal Strength meter' all functions tested for perfect operation. This receiver has an awesome FM tuner. All in all it's a VERY 'musical' and 'punchy' sounding receiver / amplifier. Looks NEAR NEW and sounds great!  Measures 19.75" wide x 6.5" tall x 13.5" deep and weighs an impressive 35 lbs unpacked. Includes our standard 90 day limited warranty.
Cond. 8.5+++
LAFAYETTE LR-5555 STEREO RECEIVER

(Cons. R.R.)
SOLD 7/25/19
SHIPPING TO WASHINGTON



(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

 

 

 



   

NEW LISTING 5/9/19
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE MARANTZ STEREO RECEIVER / CASSETTE TAPE DECK
MARANTZ 4025 'CASSEIVER' (aka MCR-425)
AM/FM STEREO RECEIVER / CASSETTE DECK

#...0181
Circa 1978-80

SOLD 7/30/19
SHIPPING TO TIM IN TENNESSEE

  Our technician has completely gone through and 'Certified' this unit.

ü We have completely gone through this unit cleaning everything including all switches, controls and contacts. VERY time consuming to properly service this unit, especially the 8-track deck. Extensive cleaning of unit internally.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Entire transport was disassembled down to the chassis, and every mechanical part was cleaned of "varnished" lubes and re-lubed as well as the always at issue, Pinch Roller plunge assembly, re-lubed and reassembled (VERY DIFFICULT and TIME CONSUMING on this unit)

ü Main drive belt has been replaced with NEW for trouble free service (#42-1975 and counter belt replace with #030).

ü Capstan flywheel removed, cleaned, burnished and re-lubed prior to re-install. Entire transport and mechanism has been cleaned, re-lubed and de-magnetized.

ü Heads have been cleaned and de-magnetized and are in great shape.

ü Head alignment and azimuth at 125Hz, 1kHz and 10kHz adjusted for BOTH directions for 'peak performance' with O-Scope and w/ STL and TEAC MTT-257H calibration / alignment tapes. Both channels now even output.

ü Meters adjusted to even zero with symmetric with Volt meter, O-Scope and w/ STL and TEAC MTT-257H calibration / alignment tapes. Both channels now even output.

ü Both Internal playback amplifier channels adjusted with Volt meter, O-Scope and w/ STL and TEAC MTT-257H calibration / alignment tapes. Both channels now even output.

ü Meters adjusted to even zero with symmetric input with Volt meter, O-Scope and w/ STL and TEAC MTT-257H calibration / alignment tapes. Both channels now even output.

ü Both Internal Record amplifier channels adjusted with Volt meter, O-Scope and w/ STL and TEAC MTT-257H calibration / alignment tapes. Both channels now even output.

ü Record signal path contacts cleaned and burnished for static-free performance

ü Linear Record switch cleaned so no 'Motor Boating' effect

 
ü Internal playback, meter and record level pots also adjusted w/ O-scope.

ü Following refurbishment, Speed checked with factory test tape to 100% accuracy! (meaning in this case, that our 1000Hz test tape plays back at 1000Hz on our Freq Counter Meter)

ü Deck 'sonically' checked for WOW and Flutter with no appreciable issues

ü Record Meters adjusted for 'even' readout and performance

ü Pinch Roller replaced with new, as following initial transport overhaul, we found that occasionally, on certain tapes the original / old pinch roller would 'crinkle / wrinkle' the tape

ü Floor noise of receiver tested @-60dBm. Floor noise of cassette deck measured with 'blank' Fuji tape at 1.75mVAC.

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! FM sounds fantastic. AM is decent as well.

ü All dial, indicator & meter lamps work or were replaced.

ü Stereo indicator lamp working

ü We also checked the heat sink compound which should be good for another 30 years.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 16+ hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.

ü On our test bench, each internal amplifier of this particular unit, #...0181, produced peak power of 16 Volts per channel for 28 Watts per channel @ 8 Ohm and 13 Volts @ 4 Ohm for 42 Watts per channel @ 1khz from actual discrete output transistors (2x 2SA1060 and 2x 2SC2484) (ALL the other 'compacts' we were working on utilized STK power pack, which had some to do with why we couldn't resurrect many of them. The DC was just too high in many cases, and couldn't be rectified practically).
ü AC Idle current at <.35A, & floor noise-60dBm.
ü DC offset checked to <30mVDC / channel (VERY good for a 'compact' unit and as good or better than many separate components).
  ____________________________
  

So, as with anything you want to look up on the 'world wide interweb', you will find a myriad of opinions. Many of them are from folks who have never even personally experienced what they are 'spouting off' about. Well, of course, I have mine too, however, mine will be from someone who does have 'personal experience' with whatever I'm 'expounding' about, and is from 'real world' experiences, 'down in the trenches'. I often get a 'kick' out of what folks have to say (generally negative) about a piece of gear, with no actual, personal experience. Recently read so many opinions of a speaker we had just finished and were about to audition, prior to auditioning them, that I was not holding out much hope for their final performance. Not only was I surprised by their actual performance (in a positive way), they were completely the antithesis of what EVERY opinion on the web stated, with NONE of them ever actually hearing them (they all stated so in their opinions). Anyway, I'll climb down from my 'ivory tower' for a moment just to say that for what this is designed to be it really came out as a wonderful unit following it's 18+ hours of service to bring it back to essentially 'new' condition. Wonderful condition, and for a 'compact system' REALLY GREAT SOUNDING, late 70's, silver face 'Combo' Receiver from Marantz. We've had this for years, but just recently got around to restoring it. We had a few 'compacts' from brands such as Sony, Panasonic, Fisher, Marantz, but most did not pan out (didn't even attempt the 'cheeeeeese' from companies like Electrophonic, GE, Lloyds, Sound Design, Symphonic and a host of other 'bottom feeder' units.

It really is surprising in sonics, performance, feel and quality
. Great performance for a 'small to mid-sized' 2-Channel audio system. This is the only the second or third 'compact' to 'pass muster' in the past couple decades (I think the last one was about 1998 or 99 and shipped to Germany and then the Panasonic we recently posted as well).
This is an INCREDIBLY ‘Musical’ sounding receiver. Lot's of surprising 'punch' and volume.
Yes, I know, it's a 'compact' and not a 'separate component', but it really is that nice!!! Enough power for up to 'medium-large' / 10" woofer speakers.
Interestingly, this unit also has the most extensive 'spec listing' of any unit we've ever posted, even over such units as a Pioneer SX-1980 (not even considering that it's 2 units in one). And, the specs are quite respectable in most aspects!

Marantz 4025 / MR425 Features:
  
Receiver
features:
-
Weighted flywheel, analog, slide rule tuning
- Separate Bass and Treble controls utilizing high quality de-tented pots
- Oversize volume control,utilizing high quality de-tented pot
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- FM Muting (separate from 'Stereo / Mono' switch)
- Stereo / Mono selector
(Separate from 'FM Muting' switch)
- LED Stereo
Indicator
- Hi filter for reducing tape hiss / electronic hiss & noise and record static

- Phono / Turntable input with Built-In Phono Pre-Amp
- Tape Input from built-in cassette deck (not for signal processor insertion)
- Tape Output RCA jacks (Record Out / 'Pre-Volume', Line Level output jacks for any Source)
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Microphone Input to tape
(be careful with your speakers if using an 'open / live' mic with home-audio speakers)
- A, B, or A+B speaker selector

- Standard 1/4" Stereo Headphone jack

- Built-in, internal AM ferrite antenna
- Externally located 'Mains' protection fuses located on rear panel
- Un-switched convenience AC outlet with 200 Watts capacity

Cassette Deck features:
- Stereo Playback and Recording 
- Super-Hard, 'Permalloy' PB / REC head
- 2-Position Tape Recording Bias selector
- 2-Position Tape EQ selector (for PB and REC)
- Dolby B NR
- Dual Back-lit, analog, Record Level VU level meters for Record and PB levels
- Separate L & R Input level controls or 'Auto-Level' Limiter
- Locking Fast Forward and Re-Wind

- 'Pause' function
- Analog / Mechanical Tape Counter

- Standard / 1/4" microphone inputs mounted on the front panel
- Microphone Input
- Rear mounted RCA I/O's

MARANTZ 4025 SPECIFICATIONS:

POWER / PRE AMP SPECIFICATIONS:
THD;
0.1% @ full rated power @ 1kHz.
Power Frequency bandwidth of power amp section; 16-30,000Hz
Frequency bandwidth of Pre-amp section; 18-24,000Hz (measured at AUX)
 IMD utilizing AUX; 0.1% @ full rated power / 20-20kHz and 8 Ohms
 Damping factor; 30 @ 8Ω full bandwidth
RMS rated Power: 2 x 25 Watts @ 8 Ohms or 30 Watts @ 4 Ohms
Headphone Jack Load Impedance; 8 Ohms
  Hum and Noise; >80dB on AUX / Tape
Input Sensitivity AUX / Tape; 180mV @ 20kΩ
Channel Balance @ 0 to -40dB / 40-16kHz;
1.5dB ALL inputs
Inter-channel Crosstalk; 47dB (non-Phono)
Record Out Levels / Impedance; 500mV / 220 Ohms @ 1kHz
Bass Control;
likely approx ±10dB @ 10hz
Treble Control; 
likely approx ±10dB @ 20khz
High Filter; -10dB @ 8kHz @ 12dB Oct!
"Loudness" Contour;  likely approx +8dB @ 50hz, +3dB @ 10khz (w/ volume set at -30dB)

TUNER SPECS FOR FM:
Tuning Range;
87.4 - 109MHz (a bit wider than most tuners!)
Freq Response;
30-15kHz (limited by FCC)
S/N (Weighted); > 62db Stereo w/ 1mV input
Usable Sensitivity @ 40kHz Deviation & @ 98 Mhz:
Mono; (1.7 uV)
Stereo; 60 uV)

Capture Ratio; 1.0dB (approx)
IF Rejection; >90dB
Alternate Channel Selectivity @ 98mHz (±300kHz); >65dB
Image Response Ratio: 50 dB
Spurious Response Rejection: 90 dB
AM Supression; 50dB
Pilot Signal & Subcarrier Rejection: 19kHz = 58 dB & 38kHz = 58 dB
THD w/ 100% modulation Mono; 0.2%
THD w/ 100% modulation Stereo0.3%
Stereo Separation; >42dB
Channel Balance;
1.0dB
Output Voltage @ 1kHz; 600mV
Output Impedance @ 1kHz; 4.4k Ohms
Ant Terminals;
Balanced 300 Ohms / Un-balanced 75 Ohms

TUNER SPECS FOR AM:
Tuning Range;
525-1620kHz
(a bit wider than most tuners!)
Useable Sensitivity @ 26dB S/N, 30% Modulation @ 1Mhz;
20 uV with ferrite stick antenna
Image Rejection @ 1 Mhz; 41dB
IF Rejection @ 1 Mhz; 55dB
Selectivity @ 1 Mhz ± 9kHz: 20dB

Spurious Response Rejection
@ 1 Mhz: 38 dB
THD w/ 100% modulation Mono; 1.0%
Freq Response; 40- ~ 2.2kHz

S/N @ 1 Mhz: > 43db

PHONO SECTION SPECS:
Freq Response;
RIAA Standard Curve +/- 2dB.

S/N;
>72 dB

Input Sensitivity;
2.7 mV @ 47
 Overload 'Margin';
31dB
Inter-channel Crosstalk;
45dB (Phono)

Cassette Deck Specifications:
 
Track format: 
4 track / 2 channel
Motors:
 1x DC Servo Controlled
Tape Speed
: 
1 7/8 ips / 4.75 cm/sec
Heads: 2x; RP Super-Hard Permalloy. Erase is Ferrite
Recording System: AC Bias
Erasing System
: AC Erase
Meters
: 
Standard VU
Overall Frequency Response (Dolby Off);

40-14kHz +/- ~3db w/ Ferric Oxide Tape @ -20dB
40-13.5kHz +/- 3db w/ CrO2 Tape @ -20dB
40-12.5k
Hz +/- 3db w/ 'Normal' Tape @ -20dB
Harmonic Distortion / THD:
3.0%
 w/ Ferric Oxide Tape @ -20dB
3.0%
w/ CrO2 Tape @ -20dB
2.2% w/ 'Normal'
Tape @ -20dB
Wow & Flutter (WRMS):
0.18% wtd
S/N ratio w/ CrO2 tape:
>52dB w/ Dolby B OFF & >58dB w/ Dolby B ON (over 5kHz and and High Bias Tapes)
Line Input Level and Impedance ('Nominal'): 22dB @ 20K Ohms
Microphone Input Level and Impedance ('Nominal'):
72dB @ 10K Ohms
Line Output Level and Impedance ('Nominal'): 500mV @ 2K Ohms
Fast Wind Time:
~105 Seconds for C-60 tape

General
Specifications:
AC / Mains Power Requirements; 120 VAC @ 60Hz
Power consumption;
Idling Current 28Watts & 130 Watts at rated Output both channels
Semiconductor Complement:
Integrated Circuits; x7
Transistors; x61
Diodes; x43
Field Effect Transistors; x1
Weight: Stand alone; 28.6 lbs / 13.0 kgs & Originally packed; 33.0 lbs / 15.0 kgs


Again, we have done the previously stated refurbishment / restoration work (~16+ hours) on this unit to insure its performance, and it gets our full 'Certification'. All functions tested for perfect operation. Overall, it is in great cosmetic condition! Looks and sounds great! Measures 22.5" wide x 6.5" tall x 16.5" deep and weighs 29 lbs unpacked. Includes our standard 90 day limited warranty.
Cond. 8.5
Marantz 4025 / MRC425 Stereo Receiver / "Casseiver"

SOLD 7/30/19
SHIPPING TO TIM IN TENNESSEE


(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 
    

 

NEW LISTING 12/14/17
(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
STEREO / QUADRAPHONIC
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE STEREO RECEIVER SANSUI QUADRAPHONIC / 4-CHANNEL / 2-CHANNEL STEREO RECEIVER
SANSUI QRX-7500 RECEIVER
#...0232
Circa 1973-75

"WORLD AC POWER"
 M.I.J.

SOLD 1/4/19
SHIPPING TO ED IN FLORIDA

ü  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü  Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is above average for a 'stereo receiver' on this SANSUI QRX-7500. 

ü All dial, indicator & meter lamps 'proactively' replaced for a TOTAL OF 26!!!

ü  We also checked the heat sink compound which should be good for another 30 years.

ü Amplifier section had output bias adjusted to spec levels of ~24.8mVDC on all four amplifiers.

ü  DC offset adjusted to VERY LOW levels on all four amplifiers.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 15 hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.
 
On our test bench, this particular QRX-7500, #...0232, 'FRONT' amplifiers each produced 18 Volts per channel for 40 Watts per channel @ 8Ω via discrete output & 15 Volts per channel for 56 Watts per channel @ 4Ω
and
REAR' amplifiers each produced 11.5 Volts per channel for 16+ Watts per channel @ 8Ω via discrete output & 10 Volts per channel for 25 Watts per channel @ 4Ω
via discrete, Metal cased, TO-3 outputs.
(AC draw at idle .5A tested. DC as follows
FR = -1.0 mVDC
FL = +1.0 mVDC
RR = +2.5 mVDC
RL = -2.5 mVDC

(Floor noise measured at >60dBm / 0.1mVAC)
 ___________________________

 
HUGE and VERY IMPRESSIVE looking, Sansui, brushed silver, QUAD receiver, surrounded by handsome, real Walnut wood veneer side plates. This unit has THE highest 'KPD-Factor' of any we've had in a long time. What's a 'KPD Factor'? 'Knobs per Dollar! You could also say it has very high 'MPD' and 'LPD' factors as well (you should be able to figure those out now). Features gorgeous, back-lit slide rule analog tuning scale with matching VU meters as well. VERY elegant and IMPRESSIVE unit when lit in a darkened room.
'Heavy' built, machined aluminum knobs and button caps, also make this unit a pleasure to 'feel'. One of the most 'fun' receivers I've used in a long time. Would love to abscond with this one myself.
Sansui QRX-7500 Features include:
  

- Quadraphonic (sometimes spelled "quadriphonic" or "quadrophonic") / Stereo receiver 
- Weighted flywheel analog tuning
- A, B, Off or A+B Front and Rear speaker positions
- Separate Front and Rear, Bass and Treble controls
- Balance controls allow complete blending between Front and Rear / Left and Right
 - Built-in Hi and Sub filters (separately switchable Front and Rear) for reducing 19kHz pilot tone in FM broadcasts, Tape Hiss and the Sub filter for reducing turntable rumble
- FM muting
- ''Function Control' selector for 2-Channel Stereo, & 4-Channel modes of ''QS Synthesizer' (To convert (synthesize) conventional, 2-channel / stereo program sources to 4-Channel stereo output), 'QS Regular Matrix' (to decode and reproduce 4-channel program sources (records, tapes and their respective broadcasts),  ''Phase Matrix' (to decode and reproduce 4-channel program sources, encoded with the CBS / SQ matrix system) or 'CD-4 / Discrete' (when wishing to hear discrete 4-channel tapes or CD-4 (Quadradisc) records).
- Aux inputs for both Front and Rear (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Dual tape monitors with Tape monitor A also featuring a DIN input as well as the standard RCA I/O's for both Front and Rear
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
-  Dual Phono / Turntable inputs with Built-In Phono Pre-Amp, featuring 'Phono-2' compatible with 'CD-4' cartridges
- Loudness control for increasing 'rock-n-roll smile' tone curve at lower volumes
- Front and Rear 1/4" stereo headphone jacks for connection of either 'stereo' headphones, or 'quadraphonic / 4-channel' headphones
- Tu
ning
DArsonval meters for tuning and signal strength
- Quad VU meters for channel levels
-'CD-4' Level adjustments located on front panel for Carrier Level, and L/R Separation of Quad discs / records.

- Rear located, full barrier strip for external antenna connections
- Rear located main AC protection fuse
- Dual AC convenience outlets on rear panel with 1 switched and 1 un-switched for a total capacity of 250 Watts of accessories
  - True “
WORLD AC POWER"

   as it will work on both 50 or 60 Hz AC and voltages from 110-240 Volts AC


Sansui QRX-7500 Original Specs:

 POWER / PRE AMP SPECIFICATIONS:
THD;
0.3% @ full rated power @ 1kHz.
 Freq Response of power amp section; 30-30kHz @ 1W
 Power bandwidth of power amp section; 10-30,000Hz ±0dB
 IMD utilizing AUX;
 0.3% @ full rated power / 20-20kHz and 8 Ohms
 Damping factor; 40 @ 8Ω full bandwidth
Dynamic rated Power: 2 x 180 Watts @ 8 Ohms or 260 Watts @ 4 Ohms

Cont rated Power:
4x 32 Watts @ 8 Ohms / 1kHz (BOTH channels driven)
4x 52 Watts @ 8 Ohms / 1kHz (each channel driven)
4x 35 Watts @ 4 Ohms / 1kHz (each channel driven)
4x 28 Watts @ 8 Ohms / 1kHz (ALL channels driven)
4x 25 Watts @ 4 Ohms / 1kHz (ALL channels driven)


  Hum and Noise; >80dB on AUX / Tape
Input Sensitivity AUX / Tape; 100mV @ 50kΩ
Record Out Levels; 100mV
Bass Control;  ±12dB @ 50hz (most amp tone controls are only +/- 10dB)
Treble Control;  ±12dB @ 15khz (most amp tone controls are only +/- 10dB)
Low Filter;  -10dB @ 50Hz @ 6dB Oct
High Filter;  -10dB @ 10kHz @ 6dB Oct
"Loudness" Contour;  +8dB @ 50hz, +3dB @ 10khz (w/ volume set at -30dB)


TUNER SPECS FOR FM:
Tuning Range;
88-108MHz
Freq Response;
30-15kHz (limited by FCC)
S/N; > 65db Stereo w/ 1mV input
Mono Sensitivity; 1.9 μV
Capture Ratio; <2.0dB
IF Rejection; >90dB
Image Rejection; >75dB
Spurious Noise Ratio; >80dB
Selectivity; >60dB
THD w/ 100% modulation Mono; 0.3%

THD w/ 100% modulation Stereo0.5%
Stereo Separation; >37dB


TUNER SPECS FOR AM:
Tuning Range;
535-1605kHz
Useable Sensitivity; 50db/m with ferrite stick antenna
Image Rejection; >80dB
IF Rejection; >80dB
Selectivity; 25dB

PHONO SECTION SPECS:
Freq Response;
20-20kHz RIAA Standard Curve +/- 1dB.

S/N;
>70 dB

Input Sensitivity;
2.5 mV @ 50kΩ
 Overload limit;
150mV w/ 0.5% THD @ 1kHz

CD-4 DEMODULATOR:
Input Sensitivity;
2.5mV (adjustable 1 TO 10mV)
Input Impedance; 50kΩ
Freq Response (STD test signal); Main Channel 30-15kHz, Sub Channel 30-10kHz

 Power consumption;
140 Watts at rated
  

Again, as stated before, we have completely gone through this SANSUI QRX-7500 Quad receiver, cleaning and testing all and it gets our full 'Certification'. Everything is in fabulous electrical and cosmetic condition! Looks near new and sounds great! AMAZING looking when lit up at night or in a darkened room! Again, this unit is a 'blast' to use. It just simply 'feels nice'!
Comes with an 'e-copy / PDF download of the SANSUI QRX-7500 owners / users manual, and the service manual if the purchaser desires.  Measures 23.5" wide x 8" tall x 14.5" deep and weighs an impressive 55 lbs unpacked. Includes our standard 90 day limited warranty
.
SANSUI QRX-7500 STEREO RECEIVER
Cond. 8.5+++

SOLD 1/4/19
SHIPPING TO ED IN FLORIDA

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 
 


 

 

 

    

NEW LISTING 1/9/19
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE MCS STEREO RECEIVER
MODEL 3235
MCS "Modular Component Systems"
 #....2761
Circa 1977-80

SOLD 2/23/19
SHIPPING TO ROBERT IN OKLAHOMA

  
ü  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Frozen / sluggish tuning meters re-adjusted for correct operation

ü Missing control switch cap sourced and modified for correct function

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years.

ü  We also aligned the tuner dial with the tuning capacitor via the 'capacitance centering' screw on the tuning cap.

ü All dial, indicator & meter lamps 'proactively' replaced w/ #658 x4

ü We also checked the heat sink compound which should be good for another 30 years.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 11 hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.

On our test bench, this particular 3235, #...2761 amplifiers each produced 20 Volts per channel for 50 Watts per channel @ 8 Ω via discrete output & 17 Volts per channel for 72 Watts per channel @ 8Ω via discrete, TO3 Metal Cased outputs (2 each 2N3055 and MJ2955)
AC Idle current at 300mA, DC offset output adjusted to <15 mVDC either channel. Floor noise measured at >-60dBm w/ AUX shorted.)
   ___________________________

   
Impressive & huge MCS 3235 (Modular Component Systems) Silver-face receiver. LOADED with features. This is the first one of this model we've had in over two decades. MCS units were usually built by either Matsushita (Technics / Panasonic) or NEC, both OEM 'giants' in the electronics industry. Only remaining 'issues' are the 'balance control' 'feels' like it 'drags'. It's been flooded with cleaner numerous times. Sonically it's fine with no static. Just 'feels' bad (most folks are not going to do much with the 'Balance' control other then leave it centered anyway) (yes, we lubricated the bushing to no avail). Also, one of the speaker output clips on the 'Rear / Matrix' is missing it's plastic tab. You can still lock in speaker wire, just need something small to press it in. Finally, and cosmetically, there's a minor scuff on the dial window (see photos above).
By design, the unit does not have a 'DC Relay' for turn-on, so there will be a thump through your speakers as the power supply caps are charging up.


MCS 3235 Features include:
    

- Weighted flywheel, analog, 'Slide-Rule' tuning
- A, B, or A+B speaker positions plus an "Off" speaker position
- 'Martrix' / Rear speaker outputs (gives a pseudo 'surround sound / quad' effect to 'rear speakers)
- 3-Band EQ section featuring Bass, Midrange and Treble
- EQ / Tone Defeat for purest signal path
- Volume control with super quality de-tented pot
- Loudness control for increasing 'rock-n-roll smile' tone curve at lower volumes
- Built-in Hi (Scratch) and Sub filters for reducing 19kHz pilot tone in FM broadcasts, Tape Hiss, AM hiss and the Sub filter for reducing turntable rumble and feedback.
- FM muting (separate from Stereo / Mono selector)
- Stereo / Mono selector (separate from FM muting selector)
- Aux inputs (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)
- Two 'True' Tape Monitors (either One or Two at once)
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)

- Bi-Directional Tape Dubbing
-  Dual Phono / Turntable inputs (one for MM cart and one for 'Ceramic')
- Front mounted 1/4" stereo headphone jack

- Dual Analog /
'd'Arsonval' meters for tuning and signal strength
- Externally located Speaker Output / Amplifier protection fuses
- Externally located AC line / mains protection relay
- Built-in, Ferrite Stick, AM Antenna
- Rear located, full barrier strip for external antenna connections
- Dual AC convenience outlets on rear panel with 1 switched and 1 un-switched for a total capacity of 320 Watts of accessories

 

Again, as stated before, we have completely gone through this MCS 3235 Stereo Receiver, cleaning and testing all and it gets our full
'Certification'. It is in fabulous cosmetic condition! Looks, performs and sounds great!
Measures 18.75" wide x 7.25" tall x 15.5" deep and weighs 30 lbs unpacked. Includes our standard 90 day limited warranty.
MCS 3235 STEREO RECEIVER
Cond. 8.5

SOLD 2/23/19
SHIPPING TO ROBERT IN OKLAHOMA

(CONS. M.H.)


(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 



    

NEW LISTING 1/1/19
(Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE KENWOOD STEREO RECEIVER
KENWOOD KR-4070 / KR4070
AM/FM STEREO RECEIVER

#...2407
Circa '77-'81
MIJ

SOLD 3/2/19
SHIPPING TO MICHAEL IN WISCONSIN

  
Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü 'Gray Box' power switch is functioning perfectly with no arc'ing or contact issues.

ü Internal fuses checked for continuity and correct values. No issues found, fortunately. We don't like seeing incorrect fuses having been installed in a unit as that could mean it had prior issues, or if a fuse value was 'increased' it could have allowed too much current through an 'ailing' circuit causing un-due / un-necessary damage.

ü Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Originally loose 'Power / Speaker Selector' and 'Input Selector' controls found to be due to disintegrated 'nylon / plastic' 'Castle nuts'. We replaced them with 'metal castle nuts' and now hold shafts and face plate solidly.

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is WAY above average for a 'stereo receiver' on this Kenwood KR-4070. 

ü All dial, indicator & meter lamps 'proactively' replaced (and tinted blue) (even though originals were working)

ü Stereo indicator lamp replaced (even though original was working)

ü We also checked the heat sink compound which should be good for another 30 years.

ü All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 7 hours.

ü Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 72 hours into a 4 Ohm load.
  

On our test bench, each internal amplifier of this particular unit, #...2407, produced peak power of 20 Volts per channel for 50 Watts per channel @ 8 Ohm and 17.5 Volts @ 4 Ohm for 76 Watts per channel via discrete output devices at 1khz. (2X NEC 2SD588 & 2X NEC 2SB618). AC Idle current at .3A, & floor noise <0.1 mVAC and Bias adjusted across emitter resistors. DC offset checked for excessive levels (no internal adjustment for DC).
  ____________________________
  

Wonderful condition, late 70's silver face receiver from Kenwood. Great performance for a 'mid-sized' 2-Channel audio system. We've had 4 or 5 of this model over the past couple decades.
This is an INCREDIBLY ‘Musical’ sounding receiver. The tone / pre-amp section very transparent and ‘glassy’ sounding, even with only the FM tuner as a source! Nice looking classic brushed aluminum face and knobs with only minor scuffs. 
  Kenwood KR-4070 Features:
  
-
Weighted flywheel analog slide rule tuning
- A, B, A&B speaker selector
- Separate Bass and Treble controls utilizing high quality de-tented pots
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- FM auto/muting and mono selection
- Dual Analog back lit meters for center tuning and signal strength
- Phono / Turntable input with Built-In Phono Pre-Amp
- 'True' Tape Monitor with a DIN input as well as the standard RCA I/O's
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

- Built-in AM ferrite antenna
- Dual 200 watt convenience AC outlets with one being switched for a total of 400 Watts capacity

Original Kenwood KR-4070 Specifications:

POWER / PRE AMP SPECIFICATIONS:
Power output: 40Wpc min RMS @ 8 Ohms & no more than 0.1% THD @ 20-20kHz
40Wpc min RMS @ 8 Ohms & no more than 0.1% THD @ 1kHz
50Wpc min RMS @ 4 Ohms & no more than 0.1% THD @ 1kHz
THD:
<0.05% @ 1 watt  / 1kHz & <0.1% @ full rated power into 8 Ohms
IHF IMD: 0.1% @ full rated power, 0.05% at 1 watt @ 8 Ohms
Freq Response of power amp section: 10-40,000kHz
Damping factor: 40 @ 8Ω / 1kHz
Power Bandwidth: 10-40,000Hz
 
TUNER SPECS FOR FM:
Usable Sensitivity:
10.8 dBf (1.9 uV)
Tuning Range:
87.4- 109.7MHz
Freq Response: 20 – 15 KHz +-.5dB, -2 dB
S/N @ 65dBf: >72db Mono or 67dB Stereo
Capture Ratio: 1.0 Db
Image Response Ratio: 45 dB
Spurious Response Ratio: 75 dB

TUNER SPECS FOR AM:
Useable Sensitivity: 6 uV
Signal to Noise Ratio:
50 dB
Image Rejection: 50 dB
Selectivity:
34 dB
 
PHONO SECTION SPECS:
Freq Response:
RIAA Standard curve +_0.3 dB, -0.3 dB
Input Sensitivity: 2.5mV @ 47K Ohms/73 dB
Maximum Phono Input Level: 190 mV, THD 0.% at 1 KHz

Again, we have done the previously stated refurbishment / restoration work (~7+ hours) on this unit to insure its performance, and it gets our full 'Certification'. All functions tested for perfect operation. This receiver has an awesome tuner. Overall, it is in great cosmetic condition! Looks and sounds great! Includes a pdf, 'e' copy, download of the Kenwood KR-4070 owners / users / instruction manual. Measures 18.5" wide x 6" tall x 16.5" deep and weighs an impressive 21 lbs unpacked. Includes our standard 90 day limited warranty.
Cond. 8.5++
KENWOOD KR-4070 STEREO RECEIVER
$499.
SOLD 3/2/19
SHIPPING TO MICHAEL IN WISCONSIN

(Cons. M.H.)



(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)

 

 

     

 

NEW LISTING 12/11/18
(click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
STEREO / QUADRAPHONIC
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE STEREO RECEIVER KENWOOD 'SUPER QUAD' QUADRAPHONIC / 4-CHANNEL / 2-CHANNEL STEREO RECEIVER
KENWOOD KR-9940 / KR-9340 RECEIVER
#...0427
Circa 1973-76

   
"WORLD AC POWER"
 M.I.J.
SOLD 1/30/19
SHIPPING TO JIM IN CALIFORNIA

ü  Our technician has completely gone through and 'Certified' this unit.

ü  We have completely gone through this unit cleaning everything including all switches, controls and contacts. Extensive cleaning of unit internally.

ü  Controls were 'flooded' w/ 'De-OxId' and are quiet

ü Tuner string checked for any fraying then re-tensioned to increase traction & relieve flywheel binding and re-centered pointer to correct dial position.

ü  We aligned the tuner front-end for optimum AM & FM performance as older internal tuner components have always drifted on vintage gear over the years. VERY GOOD TUNER! AM seems to be an 'afterthought' on many stereo receivers and component tuners. The AM is above average for a 'stereo receiver' on this Kenwood KR-9940. 

ü All dial & meter lamps checked as good, and as they are 'low current draw', should offer lots of trouble-free service.

ü  We also replaced the 'Power Switch' as the original was occasionally 'hanging up' upon release.

ü  We also replaced the AC Power Line cord as the original was 'questionable' for safety.

ü  We also checked the heat sink compound which should be good for another 30 years.

ü  Amplifier section had output bias adjusted to spec levels of ~25mVDC across emitter resistors.

ü  All inputs tested and both side produces clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine.
Total restoration time investment 11.5 hours.

ü  Following restoration procedures, the unit was run continuously at medium volume, as all our amplifier / receivers are, into a load with "Loudness" on and both Tone Controls at 10 for 48 hours into a 4 Ohm load.
 
On our test bench, this particular KR-9940, #...0427, amplifiers each produced 24+ Volts per channel for 72 Watts per channel @ 8Ω via discrete output & 20 Volts per channel for 100 Watts per channel @ 4Ω via discrete, Metal cased, TO-3 outputs (8x 2SD287).
(AC draw at idle 0.22A tested)

(Floor noise measured at 2.5mVAC)
 ___________________________

 
  Impressive huge Kenwood Silver-face receiver, surrounded by handsome, real Walnut wood veneer side plates. This unit has about the highest 'KPD-Factor' of any we've had in a long time. What's a 'KPD Factor'? 'Knobs per Dollar! You could also say it has very high 'MPD' and 'LPD' factors as well (you should be able to figure those out now). Features gorgeous, back-lit slide rule analog tuning scale with matching VU meters as well. VERY elegant and IMPRESSIVE unit when lit in a darkened room. This unit appears to have been marketed under two model numbers. The KR-9940 and the KR-9340
(likely one for North America and the other for the rest of the planet).
From original Kenwood brochures, "
Kenwood KR-9940 can function as a two or four channel receiver, having a built in regular matrix and SQ type decoders....As a four channel receiver the amplification channels work separately, each driving one of four speakers....The semi-complementary directly coupled power amplifiers have wideband and low distortion characteristics which ensure smooth, high-fidelity amplification....Two pairs of speaker terminals are available to permit simultaneous listening at two different places....A double switching demodulator is used in the MPX section to prevent carrier leaks and ensure the best sound quality".
 Features include:
  

- Quadraphonic (no it's not spelled 'quadriphonic' !!!) / Stereo receiver 
 - Weighted flywheel analog tuning
  - A, B, Off or A+B Front and Rear speaker positions
  - Separate Front and Rear Bass and Treble controls
- Balance controls allow complete blending between Front and Rear / Left and Right
 - Built-in Hi and Sub filters for reducing 19kHz pilot tone in FM broadcasts, Tape Hiss and the Sub filter for reducing turntable rumble
  - FM muting (separate from Stereo / Mono selector)
  - 'Mode' selector for Stereo / Mono, 2-Channel & 4-Channel modes of 'RM' / 'SQ Logic', or 'Discrete'.
 - Aux inputs for both Front and Rear (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)

  - Dual tape monitors with Tape monitor A also featuring a DIN input as well as the standard RCA I/O's for both Front and Rear
  (Tape Monitors can be used with Tape decks such as Cassette Tape Recorders/ Players, Reel to Reel's, 8-Track Tape Cartridge Decks, Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPad® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
 -  Dual Phono / Turntable inputs with Built-In Phono Pre-Amp, featuring 'Phono-2' compatible with 'CD-4' cartridges
  - Loudness control for increasing 'rock-n-roll smile' tone curve at lower volumes
- Dual Meter Level selector
   - Front and Rear 1/4" stereo headphone jacks
   - Rear mounted 1/4" microphone jack (be careful with your speakers if you are going to utilize this!)
  - Tuning window features dual VU meters for tuning and signal strength
  - Quad VU meters for power output level
  - FM Detector RCA output
  -
*Kenwood's KCD-2, CD-4 system, disc demodulator Adaptor slot and includes the KCD-2 adaptor that is often missing on these models
 - Rear located, full barrier strip for external antenna connections
- Rear located main AC protection fuse
  - Triple AC convenience outlets on rear panel with 1 switched and 2 un-switched for a total capacity of 160 Watts of accessories
  - True “
WORLD AC POWER"

   as it will work on both 50 or 60 Hz AC and voltages from 110-240 Volts AC


Original Specs:
  
"The KR-9940 has a 'Direct-Coupled / DC' amplifiers that produce continuous power output of 40 Watts per channel min. @ 8 Ohms from 20 hertz to 20,000 hertz with no more than 0.5% THD (measured utilizing AUX input)"
 
Original Kenwood KR-9940 / KR-9340 Specifications:

 POWER / PRE AMP SPECIFICATIONS:
 THD;
0.5% @ full rated power or 0.1% @ 50% rated power @ 1kHz.
 Freq Response of power amp section;
 @ full rated power 20-20kHz
 Power bandwidth of power amp section; 10-50,000Hz ±0dB
 IMD utilizing AUX;
 0.5% @ full rated power / 20-20kHz and 8 Ohms
 Damping factor; 30 @ 8Ω full bandwidth
Dynamic rated Power: 2 x 240 Watts @ 8 Ohms or 340 Watts @ 4 Ohms
Cont rated Power:
4x 40 Watts @ 8 Ohms / 20-20kHz
4x 44 Watts @ 8 Ohms / 1kHz
4x 55 Watts @ 8 Ohms / 1kHz


  Hum and Noise;  75dB on AUX / Tape
Input Sensitivity AUX / Tape; 150mV @ 50kΩ
  Tape 1/2 Output level, via RCA; 150mV @ 50kΩ
  Bass Control;  ±10dB @ 100hz
  Treble Control;  ±10dB @ 10khz
  Low Filter;  -8dB @ 100Hz @ 6dB Oct
  High Filter;  -6dB @ 5kHz @ 6dB Oct
  "Loudness" Contour;  +10dB @ 100hz, +5dB @ 10khz (w/ volume set at -30dB)

PHONO SECTION SPECS:
 Freq Response;
20-20kHz RIAA Standard Curve +/- 1dB.

 S/N;
60 dB
 Input Sensitivity;
1.5 mV @ 50kΩ
 Overload limit;
100 mV w/ 5% THD @ 1kHz

TUNER SPECS FOR FM:
 Freq Response;
20-15kHz
 S/N; > 63db Stereo w/ 1mV input
 AM Suppression; 60dB
 Mono Sensitivity; 1.8 μV
 Capture Ratio; 3.0dB
IF Rejection; 90dB
  Spurious Noise Ratio; 90dB
 THD w/ 100% modulation @ 400Hz, Mono;  0.7%
 THD w/ 100% modulation @ 400Hz, Stereo;  0.8%
Stereo Separation; 40dB at 1Khz & 20dB @ 10kHz
 FM Alternate Channel Selectivity; 50dB

  TUNER SPECS FOR AM:
  Tuning Range;
530-1600kHz
  S/N; > 45db w/ 1mV input
  Useable Sensitivity; 25μV / m with ferrite stick antenna
Image Rejection; 45dB
IF Rejection; 35dB
  Selectivity; 30dB

 Power consumption at max output;
550 Watts. 38 Watts w/ no signal at idle
  

Again, as stated before, we have completely gone through this Kenwood KR-9940 Quad receiver, cleaning and testing all and it gets our full 'Certification'. Everything is in fabulous electrical and cosmetic condition! Only issue is a previous owner engraved id number in corner of top panel (visible from over head. see photos above). Looks near new and sounds great! Very nice looking when lit up at night or in a darkened room! Comes with an 'e-copy / PDF download of the Kenwood KR-9940 service manual if the purchaser desires.  Measures 21.5" wide x 6.5" tall x 14.5" deep and weighs an impressive 47 lbs unpacked. Includes our standard 90 day limited warranty
*.
  KENWOOD KR-9940 STEREO RECEIVER
  Cond. 8.5
w/ KCD-2 Quadraphonic adaptor installed
(Cons. R.R.)
SOLD 1/30/19
SHIPPING TO JIM IN CALIFORNIA

 
*warranty does not cover the accessory, Kenwood KCD-2, phono decoder / adaptor 'plug in' module, as there's too many variables with quad capable cartridges, records, tastes and user abilities.

(Above text, in it's entirety, property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 
 

 


 

   

 

   

  

    

     


         NEW LISTING 11/5/16

  (Click on above thumbnails to enlarge photos)
CheckMarkSmall_web.jpg (792 bytes) warranty
RESTORED / REFURBISHED / FULLY SERVICED
VINTAGE
PIONEER STEREO RECEIVER
PIONEER SX-1980 RECEIVER
PIONEER'S FLAGSHIP
THE 'BIGGEST' 'BADDEST' RECEIVER TO EVER COME OUT OF THE PIONEER FACTORY
HUGE POWER AND SIZE!
340+ Watts PER CHANNEL!!!
"NOT FOR THE 'FAINT OF POCKET-BOOK'
"
#...0723
Circa 1978-79
MIJ

SOLD
SHIPPED TO MONTANA


ü Our technician has completely gone through and 'Certified' this unit. Everything was cleaned inside and out including all switches, controls and contacts. Extensive cleaning of unit internally.

ü Power Supply circuit board and both driver boards had all of their 'electrolytic capacitors' replaced (a note on this; prior to replacing the capacitors, we 'dialed the unit in perfectly' for DC offset, Bias and clean output sine waves to beyond rated power. After replacing all the Electrolytics on the power supply circuit board and the amplifier driver boards, the unit was again measured to perfect levels. The old capacitors ALL checked fine, so basically we have baggies of about 50, 35 year old capacitors that are in fine shape. Just FYI.)

      

     


ü Control potentiometers were 'flooded' w/ 'De-OxId' and are quiet (very difficult to do as 'tone' section must be painstakingly removed).

ü ALL Switches were flooded with cleaner with emphasis especially on the always at issue, switches / controls such as the 'Function' selector, 'Tape Monitors', '-20dB Muting', and 'Tone Bypass'.


ü  Internal fuses checked for correct value / function and replaced where necessary (and there were some 'in-correct' values we found).

ü  World AC Power correctly set for North American current.

ü This unit has a tuner based on the other Pioneer models, with a couple of additional circuits. The additional circuits are the 'Quartz Lock' and the 'Fine Tune', both of which are indicated by LED's near the 'Stereo' LED indicator. These two additional circuits are an issue with SX-1980's we've discovered, and escalating the unit to an outside tech firm, did not improve their function. While the unit's tuner sounds great, it will drift after being left on for a few hours. Could be 2 or could be 24, but it will drift and need a slight 'nudge' on the tuning knob to bring it back into station center. Also, the 'Fine Tune' light is on when the station is slightly 'off center', and not when it's perfectly tuned. Both our senior techs and two outside repair shops, 'senior techs' spent 8-10 hours on these two aspects, with no appreciable improvement. The 4th tech discovered that the unit could be put into a mode which defeated the additional circuits (which when left intact caused a very faint, cyclical noise), so now it functions like the tuner on the Pioneer SX-1280, 1080, 980. Sonically the tuner sounds great, pulls in stations fine, has great side band rejection, and great 'Stereo' sound. Only issue is the above mentioned 'drift' after a few straight hours of running.

ü  We of course aligned the tuner front-end on both AM & FM bands for optimum performance as older tuner components will have 'drifted' over the years.

ü  Amplifier section had output bias and DC offset adjusted to spec levels

ü  We bought ALL the remaining AEL-029 dial bulbs from Pioneer a few years ago. These are the original, official 'Stanley 8V' with blue tinting. We purchased a couple dozen and are probably worth their weight in gold. We have not used them on any of our Pioneer restoration, and have been using a fine substitution. We were saving them for a Pioneer SX-1980 to come along. Well, this unit got them. All four dial lamps and meter lamps replaced with ORIGINAL PIONEER AEL-029's. The balance of the light bulbs, including ALL indicator lamps, the dial pointer lamp, Speaker indictors, 'Stereo' indicator, input / function indicators were replaced with new.

ü All 4
power supply filter capacitors independently tested.

ü All inputs tested and both sides produce clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads!

-VERY GOOD FM TUNER!
- FM reception as well great and IMPECCABLY CLEAN!!! All inputs tested and both sides produce clean and even sine waves into 'brick-wall' 8 & 4 Ohm loads! No power supply hum of any kind. It's dead silent! All functions test fine. Following restoration procedures, the unit was ran continuously at medium volume, as all our amplifier / receivers are, into a 4 Ohm load with "Loudness" on and both Tone Controls at 10 for 48 hours into a 4 Ohm load. Cosmetically, the top, horizontal edge of the face plate has some light / shallow striations running it's length, there's a scuff on the volume knob, and at some point in it's past, the Walnut, wood 'half bonnet' was re-veneered in a lighter shade of walnut (see photos above). Again, overall this is a fabulous receiver. You won't be disappointed. Total restoration time investment between two senior techs ~38 hours.  

ü  On our test bench, the internal amplifiers of this receiver #...0723 produced 45 Volts per channel @ 8 Ohms with 1KHz input for 253 Watts and 37.4 Volts per channel @ 4 Ohms with 1KHz input for 349 Watts via discrete outputs with 1 kHz input.
 AC Idle current @ .7A,
DC balance adjusted to 0 ±3mVDC and DC offset output adjusted to <~30mVDC either channel. Floor noise measured 0mVAC / >60dB either channel.
   ____________________________


The Pioneer SX-1980 Stereo Receiver. This is the first one of these we've had in 19 years. Even as a Pioneer dealer, back in the day, the stores I worked at didn't carry this model as it was generally TOO EXPENSIVE for the market (equaling about 10% of the average persons yearly take-home pay).
Classic looking brushed-aluminum silver face and encased in a real wood Walnut veneer cabinet with solid Walnut wood corner caps. This is the most SERIOUS receiver Pioneer ever marketed and as listed above, this one has been 'certified' following the refurb by Oak Tree Vintage and is in incredible condition!!! 
An interesting note on this one is that the consignor picked it up from a member of the Denver based, 1970's band, 'Sugar Loaf'
(famous for hit's such as "Green Eyed Lady" and "Don't Call Us, We'll Call You"). It was speculated to have been the amp in their practice space.

Pioneer SX-1980 Features:
 

Tuner features:
- Weighted flywheel analog "slide-rule" tuning
- FM Muting Selector (separate from the 'Stereo' selector)
- Dual analog 'Signal Strength' and 'Tuning' VU meters
- FM Multi-Path Detector (handy when installing antenna for best positioning)
- Dual position FM De-emphasis selectable for 25 or 75 msec 

Pre-Amp / 'Control Amplifier' / Power Amp features:
- Direct Coupled (DC) Power Amp architecture
- A or B or C, or A+B or A+C, or Off speaker selector
- Defeat-able 4-control / 2-band EQ. (Bass controls centered at 50 or 100 Hz and Treble @ 10k or 20kHz)
- Super quality de-tented Tone and Volume controls
- "Loudness" function to boost Bass and Treble in relationship to Mid frequencies at lower volume levels for a much fuller sound.
- Stereo / Mono selector (for entire pre-amp section, not just FM tuner)
- Hi filter for reducing tape hiss / electronic hiss & noise and record static
- Built-in 'Low' Filter to eliminate excess rumble from sources such as turntables
- Pre-Amp Out / Power-Amp Input / Loop
- Dual analog 'Power' VU meters
- -20dB Audio Muting for instant lowering of volume without adjusting the volume control. Great for ringing phones and cuing a record on your turntable

Inputs:
- Dual Phono / turntable inputs with Built-In Phono Pre-Amp
- Dual tape monitors with standard RCA I/O's (Tape Monitors can be used with Tape / Video / CD / DVD / VCR / DAT / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS® CDR (CD recorders as well as for inserting signal processors, such as EQ's, Reverbs, Spatial Enhancers / Dynamic Processors, Noise Reduction units, Special Effects units, Time Delays, etc)
 - Tape 'Dubbing' capability for Tape 1 to Tape 2
- Aux input (may also be used for Video / CD / DVD /DAT / VCR / MP3 / iPod® / iPhone® / iTouch® / i-gadget / MP3 / XM® / SIRUS®  etc.)
- Microphone input (be very careful with your 'home audio' speakers when inserting a mic into any stereo receiver)
- 1/4", stereo headphone jack
- Dual Phono inputs with phono 2 doubling as the Microphone input
- 4- Position phono cartridge loading selector with settings at 100, 200, 300 or 400pf for fine tuning phono pre-amp
- 3- Position cartridge impedance selector with settings at 10k, 50k, or 100k for fine tuning phono pre-amp
to your cartridge (a must for serious vinyl players)
- 1/4" front mounted Microphone input
- -20db Audio Muting

Other:
 - Pre-out / Main-in loop
 - 3 AC outlets (1 switched / 2 un-switched) for a total capacity of 300 Watts


Original Pioneer SX-1980 Specifications:


  "The Pioneer SX-1080 has a continuous power output of 270 Watts per channel min @ 8 Ohms, from 20 hertz to 20,000 hertz with no more than 0.03% THD (measured utilizing AUX input)"
 
POWER / PRE AMP:

THD:
0.02% @ 135 Wpc @ 8 Ohms & 0.03% @ Full Rated Output @ 8 Ohms
Freq Response of power amp section:
@ full rated power 20-20kHz. @1W it's rated down to 0.006%
Potential frequency response of power amp section @ 1w:
5 Hz to 100 KHz, +0 dB, -3 dB
IMD utilizing AUX: 0.03% @ 270 Wpc 20-20kHz
0.02% @ 135 Wpc 20-20kHz
0.006% @ 1 Wpc 20-20kHz

Hum / Noise (S/N) Ratio: 120dB (10 db greater than the Pioneer SX-1080)
Damping factor:
40 @ 8Ω full bandwidth
Power Amp Input Impedance:
50k Ohms
Power Amp Input Sensitivity for Full Output:
2V (coupled with the 2V output of the pre-amp, has a lot to do with the VERY high S/N listed above)
Tone Control ranges:

Sub Bass: +/-5dB @ 50Hz
Bass:
+/-10dB @ 100Hz
Treble: +/-10dB @ 10kHz
Upper Treble: +/-5dB @ 20kHz
Hi Filter: 6
KHz, 12dB/octave
(most are 6dB/ octave)
Lo / 'Sub' Filter: 15Hz, 12dB/octave (most are 6dB/ octave)
Loudness Contour: + 6dB at 100 Hz, + 3dB at 10KHz at -40dB on volume control
Pre-Amp Input Impedance: 50k Ohms
Pre-Amp Input Sensitivity at all inputs except phono & mic: 150mV
Microphone Input  Sensitivity / Impedance: 7.5mV / 50k Ohms
Input Freq Response (except Phono & Mic): 5-80kHz
Tape Output Impedance: 50kΩ
Tape Output:
150mV

Pre-Amp Output
Level & Impedance: 2V / 1k Ohms (coupled with the 2V input of the power-amp, has a lot to do with the VERY high S/N listed above and double the SX-1080)
Pre-Amp THD @ rated output: <0.01%

TUNER SPECS FOR FM:
Freq Response:
The full 30-15kHz per FCC Regulations
S/N:
 > 85 dB Mono @ 65dBf
S/N: 
> 75 dB Stereo @ 75dBf
Useable Mono RF Sensitivity dBf / μV:
8.7dBf / 1.5μV
Capture Ratio:
1.0dB
Signal for 50dB quieting, Mono dBf / μV:  
11.5dBf / 2.2μV
Signal for 50dB quieting, Stereo dBf / μV:  36dBf / 34μV
De-Emphasis: selectable 25 or 75 μ-sec
THD w/ 100% modulation @ 100Hz, Mono: 
0.05%
THD w/ 100% modulation @ 1kHz, Stereo: 
0.07%
THD w/ 100% modulation @ 6kHz, Mono:  0.02%
IF Response Ratio: 
120dB
(20db greater than the Pioneer SX-1080)
Stereo Sub-Carrier Rejection: 
65dB

AM Carrier Rejection:
60dB
(5db greater than the Pioneer SX-1080)
Spurious Rejection:
120 dB
(30db greater than the Pioneer SX-1080)
Image Response Ratio:
120 dB
(30db greater than the Pioneer SX-1080)
FM Alternate Channel Selectivity: 
80dB
Muting Threshold dBf / μV:
19.2dBf / 5μV
Stereo Separation:
50dB @ 1kHz or 40dB @ 30-15kHz

TUNER SPECS FOR AM:

RF Sensitivity: 300uV/meter or 15uV @ binding posts
Alternate Channel Selectivity:
26dB
IF Response Rejection Ratio:
70dB
(30db greater than the Pioneer SX-1080)
Image Response Rejection Ratio:
70dB
(30db greater than the Pioneer SX-1080)
Signal to Noise Ratio:
55dB
(5db greater than the Pioneer SX-1080)

PHONO SECTION SPECS:
Freq Response:
20-20kHz ±0.2dB
S/N:
87dB, ref 'shorted' input (11dB greater than the PIoneer SX-1080!!!)
Input Sensitivity:
2.5 mV with load selectable 10k, 50k or 100kΩ
Overload limit:
300 mV @ 1kHz w/ THD of 0.03%
Cartridge Load Capacitance: 100,200,300,400pF


Huge power supply in the Pioneer SX-1980 featuring Dual independent, toroidal transformers (in one housing) for a 'TRUE DUAL POWER SUPPLY', followed by 4X 100V / 22,000μF power supply filter caps to feed the huge output transistors.
Again, we have completely gone through the Pioneer SX-1980 Stereo Receiver, as stated above and 'certified' it's ready to go!
The only 'performance' issues would be the previously mentioned tuner LED's in FM mode, and cosmetically, the scuffs on the top, horizontal face edge, the volume knob scuff and the lighter, real wood Walnut cabinet.  Unit looks great and sounds HUGE! This is truly one of the "BIGGEST BOYS" when it comes to CLASSIC STEREO RECEIVERS! Includes a pdf, 'e' copy, download of the Pioneer SX-1980 owners / users / instruction manual, Service manual and original brochure if the purchaser so desires. Measures 22.25" wide x 20" deep x 8.25" high and weighs a HEAVY 73 lbs unpacked. Includes our 90 day limited warranty!
PIONEER SX-1980 STEREO RECEIVER
 Cond. 8.5
$6,300.00
SOLD
SHIPPED TO MONTANA

(Cons.) M.R.

links to a couple of "Shoot Out" articles featuring the SX-1980;


https://www.cnet.com/news/how-can-30-year-old-receivers-sound-better-than-new-ones/

http://www.iavscanada.com/receiver-shoot-out-vintage-vs-high-tech/

(Due to the dimensions and / or weight of this receiver, Packing / Shipping will be somewhat more 'involved' than typical. A custom built box may be necessary to order. While we order custom built boxes often, this can sometimes delay shipping by 5-10 days)

(Above text property of www.oaktreevintage.com / Oak Tree Enterprises, LLC. See 'Copyright Information' page for details)
 

 


 



Did you know?
Sansui was founded in 1947, just after WWII as a company manufacturing transformers (one of the most important components of any audio system). During the Sixties they morphed into what would become one of the most well respected companies in quality audio gear. I have owned and sold some incredible Sansui stereo gear from the Seventies and early Eighties. I worked at a Sansui dealer in the early part of the Eighties. Sansui remained a major force in stereo gear until about the mid Eighties, when the vast majority of audio gear started suffering from the 'how cheaply can we get it' syndrome by consumers, thus manufacturers followed suit, by building cheaper and cheaper gear.

 

 

 

   
 

 

 


We've moved the "SOLD / ARCHIVED" items to their own page.
Click ........HERE.


 


**
"(actual as measured)" refers to original test results done by Hirsch-Houck Laboratories upon test release of product when new. Current "aged" specifications / performance may of course vary from that.

 

 

 

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