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Pioneer SX-737

AM/FM Stereo Receiver (1974-76)

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Pioneer SX-737


The SX-737 is a high-quality stereo receiver featuring 35 watts per channel, min RMS at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.5% total harmonic distortion.

It has the power to do the job - not too much and not too little.

Pioneer's medium-powered SX-737 stereo receiver doesn't waste watts, yet it gives you the latest state-of-the-art advantages for versatility and true high fidelity performance.

The FM front end is equipped with a frequency-linear 4-gang variable capacitor and dual-gate MOS FET.

New dimension in FM reception stability is assured by its multiplex demodulator with the revolutionary PLL (Phase Lock Loop) circuit, while the FM IF section is equally advanced with its 5-stage limiter and phase-linear ceramic filters.

The results in FM performance are impressive: 1.9pV (IHF) sensitivity: better than 60dB selectivity: capture ratio of 1.0dB (IHF); and stereo separation of more than 30dB over the 50 to 10.000Hz range.

Accurate high fidelity reproduction of all sounds is achieved by using a particularly precise phono equalizer in the Pioneer SX-737 - it keeps RIAA deviation within ±0.3dB.

As a stereo control center the SX-737 is hard to beat - there are two stereo pairs of tape deck connections with monitoring and tape-to-tape duplication facilities (deck 1, deck 2), a function switch to allow control of the FM and AM tuner sections, a stereo Phono, a microphone and a stereo AUX.

As a bonus, and a feature you'll appreciate all the more with use, there is a unique Recording Selector to permit you to record FM broadcasts while listening to disc reproduction and vice versa. This receiver does the job.


Tuning range: FM, MW

Power output: 35 watts per channel into 8Ω (stereo)

Frequency response: 15Hz to 40kHz

Total harmonic distortion: 0.5%

Damping factor: 40

Input sensitivity: 2.5mV (mic), 2.5mV (MM), 150mV (DIN), 150mV (line)

Signal to noise ratio: 65dB (mic), 70dB (MM), 95dB (line)

Output: 150mV (line), 30mV (DIN)

Speaker load impedance: 4Ω (minimum)

Semiconductors: 1 x FET, 3 x IC, 46 x transistors, 22 x diodes

Dimensions: 500 x 158 x 410mm

Weight: 13.2kg

Accessories: FM T-type antenna

Year: 1974


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Reviewed Jan 31st, 2020 by

fantastic vintage receiver. Built like a tank,nice wood case, solid feel, quality smooth controls, crystal clear amp, I don't listen to radio much these days, but when I do, it's spot on. I use it mostly for phono and it rocks!

Reviewed Aug 04th, 2019 by

This is my best receiver, and I had a few... Fm is fantastic and amplifier as well, I was searched long time a receiver that satisfy me, after this receiver I had stopped searching..

Reviewed May 10th, 2019 by

fantastic receiver

Reviewed Mar 12th, 2018 by

I have one bought on EBay. And because we had problems with the freight, I received a complete refund from Ebay. After this, I bought a new front panel (the original arrived broken) and changed. The receiver was like new. And, yes, the sound is fantastic. Warm, deep bass, trebles and mids excellents. Old school. Now, I’m using him with a Sony turntable, CD Marantz (linked in AUX) and decks Marantz and Akai. This receiver will die with me.

Reviewed Dec 06th, 2017 by

Picked this up for $5 at a local yard sale and it was worth every cent. The unit needs some TLC and cleaning but it is working considerably well for its age. Very powerful sound.

Reviewed Oct 23rd, 2017 by

That's my better amp!

Reviewed Jun 20th, 2017 by

Nice warm sound and the 35 watts seem like a strong 35.

Reviewed Nov 21st, 2016 by

My main system is getting a recap, so I've been listening to my SX-737. What a beauty!

A gorgeously sweet, tubey sound (lots of even-order harmonics anyone?), but still enough resolution to let us audiophile music lovers hear all that detail we crave.

I don't know if I am going to go back to listening to my fancy-pants, pi-amped system after getting used to this stellar Pioneer unit!

Reviewed Jul 08th, 2016 by

I recently bought one these beautiful receivers, as it was it sounded very clean and comfortable.
However it was in bad need of a complete service, so I stripped it down and cleaned all the switches and controls and the speaker relay.
I then set about replacing the capacitors in various sections with polypropylene, Elna Silmic11 and Panasonic FG types

First stage was the regulator board, there are two transistors on here both run red hot, one has a tiny heat sink and the other nothing.
I put a larger heat sink on one and put a heat sink on the one that had nothing, despite these transistors running red hot there was no scorching to the board or dry joints.
The caps I replaced with Panasonic FG types.

The Phono stage I did with polypropylene input and output caps and Panasonics for the decoupling caps.

The control amplifier I used Elna Silmic11 caps in the audio sections and FG’s for the decoupling

I replaced the Tuner output caps with Nichicon gold caps and decoupling with Panasonic FG’s.

The input to the power amplifier was done with polypropylene caps and the rest with Panasonic FG’s.

The result a very mellow and inviting sound that is a pleasure to listen to.

There is an error in the service manual regarding the pre-sets to adjust for DC-offset and Idling current adjustment, they are round the wrong way, VR-3/4 are DC Offset adjuster and VR1/2 are the idling current adjusters

Reviewed Mar 25th, 2015 by

Old school watts!
Very powerful for it's stated output.

Will drive virtually any speaker to listening levels that are comfortable.

Reviewed Feb 11th, 2015 by

I think its important to start off by telling you I just got into buying vintage receivers. I've always liked the look of them and thought maybe ill just buy one for my bedroom. I wanted to give it a test run in my living room first. This is where I have my Marantz 5 channel 175 watts discrete..also known as the mm9000. Im using a Pioneer elite 53 as my prepro. So I disconnected my speaker wires and hooked them up to my Pioneer sx 737. I didn't realize that in the next 5 minutes...all the things that I believed in audiophile world be changed for life. I was shell shocked when I heard this pioneer pump out the first Billy Joel song on his greatest hits cd. I was like..you got to be kidding me....Its like I finally know what true audiophile sound, sounds like. The detail and the punchy bass was incredibly. I had goose bumps. Speechless song after song. The detail is so incredible that I had to double check certain cds...because there was static. I thought the receiver had a bad transistor or something...but no...it was picking up cd artifacts. Crazy! Lets talk about the strong points of this receiver. Strong tight bass, clear, accurate, warm sound...The midrange is so incredible, very pronounced..you'll hear ever word. Im using Energy RC 30s. They never sounded so incredible. I think its a match made in heaven. I have a collection over 100 dts recorded sound tracks and I don't think ill be listening to 5.1 surround anytime soon. Im back in the two channel phenomenon.

I should give this a 10..but I had to deduct points because I can hear a faint fm noise from my aux. (I have 4 other different vintage receivers and they're dead silent). I heard this is a common problem. I also changed one of the two big capacitors. it was leaking. I replaced it with a Nichon..the other is the Elna. Works perfect together. The FM tuner is a bit off but what do you expect for a receiver that is over 30 years old.

Reviewed May 29th, 2014 by

Very nice sound from this vintage Pioneer
SX-737. Clean and crisp and has that awesome wood look. Love vintage Pioneer Receivers.

Reviewed Dec 02nd, 2012 by

This is the most powerful 35 watts I have ever heard. It shames the new garage 90 watt Sony receiver. This is really all the power you will ever need in a mediuum/small room. All music forms play well. It is a bargain against the high powered vintage receivers and its build and sound exceeds the vintage marantz recievers. A pleasure to own.

Reviewed Sep 13th, 2012 by

The Pioneer SX737 Receiver produces a warm mellow sound quality reminiscent of valve amps,
coupled with a nice bass and impressive looks, electric cool blue display this receiver
has more than stood the test of time.



re: SX-737

kjasey, do you have any links on how to fix the faint FM? Thank you.

karodimitrov's picture

re: SX-737

I apologize for the my intervene, but when stations are weak - no other treatment except to turn off muting(for better tuning because sometimes can not be heard).The other option is to do a better antenna,but weak stations always noisy and sometimes necessary to cut treble or even to switch in mono.
Personal experience with my receiver Technics SA-5600X.

re: SX-737

I have one of these from my old hippie days and the speaker channels on the right do not appear to work on sets a or b. Both speakers test out ok on left side. What can i do to fix this?

re: SX-737

Have you cleaned all the switches and pots? that'd be the first starting point.

DAB Analog switch off

I have a 737 which performs absolutely brilliantly, with fantastic FM reception.
Does any one have info on what happens to such beautiful pieces of equipment
should the 2015 analogue switch off go ahead, is there any type of conversion
that can be used to allow the use of such equipment to continue.
This also applies to many other fine HI-FI receivers

re: DAB Analog switch off

Hi Monsieur Davenport,

Here in Canada, the digital conversion was supposed to happen about 4 years ago (when you posted your post). There is still analog radio here. Are you in the UK? Is there analog radio or has it all gone digital?

Time to organize and resist the takepver of our commonwealth - both the airwaves AND the internet!

noise Sx-737

I have my SX-737 has a noise problem as when you fry an egg, and so far nobody has given me an explanation of the problem or could be.

The symptom occurs with the volume to zero, and no receiver or source connected to the potentiometer that is clogged, this happens after a while and only for the right channel.

Someone could give me a direction that the review or where to start?


re: noise Sx-737

..an old query I realise... but that problem sounds like the differential pair on the input to the power amp ..its a VERY common problem with the Pioneer x3x series ... google it. There are a few youtube vids detailing the repair .. could be on a 434, 535, 636 etc..but all have the same diff. pair input stage to power amp. From memory its a 2sa725/6 that is the culprit. It starts crackling like an frying egg after a few mins ... often only on 1 channel .. pretty easy repair .. lots of available transistor replacements for the 725. Good luck

re: noise Sx-737

Could be a power relay being dirty

re: noise Sx-737

Most of the problems are old electrolytic capacitors. Use only fresh (!) high quality new ones. Use 0.5 -0.8mm solder only, and lots of for bad points.

re: noise Sx-737

I agree with you, there's a lot in those 35 years, they are already at the end of life. Capacitors lose efficiency already at 15 years old ...
Right now I'm open with a 737, was the pair Q1 and Q3 with thermal noise. When I put the selector on AUX position., PHONO to go through to make adjustments, I found more thermal noise, this time on both channels. Still have not researched the issue, but it is easy: replace all transistors ...
I also found an error in the schema, on page 22, power amp, and dc current adjustment: adjustment to dc, the right is the VR3 and VR4 (10K), and is the current setting VR1 and VR2 (100R). Pay attention.

Carlão Vintages - Brazil

re: noise Sx-737

Hi Usually this problem is related to thermal noise, caused by problems with transistors. Use a researcher signal, or a small amplifier (can be amplified in a box pc), and go searching in the pre terminals of transistors, and then the output amplifier. You will see that the noise happens in a forward part of the circuit, so pay attention to this site transistors. If the touch probe or amplifier input on a terminal of some transistor, and the noise occurs, then it is this component that is defective. replace with a new one.

Carlão Vintages - Brazil

sx737 noise

If so then it could be capacitors, output transistors, transistors on the power amp board, wire wrap terminals. Sorry but there are alot of things that go bad at age 35.

00Snake's picture

SX-737 Sound Issue

My SX-737 Pioneer Stereo Receiver works fine, but sometimes the sound goes off all of a sudden regardless of the function (AM, FM, Phono, AUX, Mic). The sound sometimes goes off for hours, and sometimes for just a few seconds before it goes on again.
I have no idea what the problem might be, so any help will be truly appreciated.

The protection circuit

The protection circuit could be the problem, look at the protection circuit board and remove Q6, this will inhibit the protection circuit but still give the power up sequence.

re: The protection circuit

i have the same problem with the protection circuit, i did what you said about the Q6 and it did come on,
the power of the red leads should only be 35V it is 47V and at the white lead it 47v too it needs to be 9V for the relay to go on, i had tried everything i can think of, i replaced bad diodes, capacitors, transistors, and still could not get the volts down where the unit will turn on, i thought it mite be the relay so i replaced that too, so it turns on now with out the Q6 there but can you tell me what the correct fix is i really would appreciate it.

thanks ted

re: The protection circuit

Did you ever get this problem corrected. I have the same problem and would like to repair it. any advise?

re: The protection circuit

I was the same, in my case only the change of place, had it cornered, I put it where I had more contact with air and until now no longer cut.

Sx 737 channel A cuts out

So you say to remove Q6, does that mean unsolder the transistor from the curcuit board? It seems like the overload protection is cutting in prematurely. Is there an easy fix?

Loss of sound

I have a SX 780 that seems to have the same issue. I think it is a protection relay as I don't hear the click after the unit powers up sometimes and others it comes on and plays for a short time and then loses the sound. I am still looking for an answer but it is looking like I am going to have to take it in for service. $60 deposit and $85 an hour. I only paid a hundred for the unit and it is in pristine condition but I am choking on the repair cost.

re: Loss of sound

hi mine does the same turn power on then a click in 5 sec.a month later turn on and no click after 5sec. then it turns off after 20 sec.
did you have yours repaired if so what was the problem ?

re: Loss of sound

did you ever get this problem corrected? if so how?

re: Loss of sound

hi mine does the same turn power on then a click in 5 sec.a month later turn on and no click after 5sec. then it turns off after 20 sec.
did you have yours repaired if so what was the problem ?


Se les agradece el que esté publicado este manual de servicio, me permitirá darle vida a mi SX-737 y repararlo de acuerdo a parametros de fabrica.


Carlos Bocca T


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