Pioneer SX-636

This Pioneer SX-636 was a mid-range offering from Pioneer in 1974 and retailed for $350.00. It only produces 25 watts per channel into 8 ohms but, as Pioneer stated in their marketing brochure:

Not all high fidelity situations require high powered equipment. If your listening room is of average size, and what you really want is more efficiency and more sophisticated versatility in a medium-powered model, Pioneer’s new SX-636 will be a good choice.”

The SX-636 came out a few years before the wattage wars so 25 wpc didn’t seem inadequate. And it wasn’t for most listening situations. Besides, the receiver looks good and has a number of features that lower end receivers don’t have.

The front panel has bass and treble controls, high filter, mono and loudness switches, and a function control for FM, AM, PHONO, MIC and AUX. The blackout style, FM-linear dial scale has two tuning meters, illuminated program indicators, and a stereo headphone jack. The control switches are push button instead of the toggle style you see on many of the later model Pioneers. The illuminated dial pointer is a nice touch as well.


  • Tuning range: FM, MW
  • Power output: 25 watts per channel into 8Ω (stereo)
  • Frequency response: 20Hz to 30kHz
  • Total harmonic distortion: 0.5%
  • Damping factor: 35
  • Input sensitivity: 7mV (mic), 2.5mV (MM), 150mV (DIN), 150mV (line)
  • Signal to noise ratio: 65dB (mic), 70dB (MM), 90dB (line)
  • Output: 150mV (line), 30mV (DIN)
  • Speaker load impedance: 4Ω (minimum)
  • Semiconductors: 1 x FET, 3 x IC, 33 x transistors, 17 x diodes
  • Dimensions: 480 x 147 x 405mm
  • Weight: 11.2kg
  • Year: 1974

The cabinet is wood grain vinyl and doesn’t look too bad.

The Pioneer SX-636 has a good tuner section and a very good phono section. The FM tuner utilizes a low-noise FET and a 3-gang variable capacitor in the front end. High fidelity sound reproduction is achieved with a precise phono equalizer that keeps RIAA deviation within +- 0.5dB.

As mentioned above, the direct-coupled OCL power amplifier provides continuous power output of 25 watts per channel at 8 ohms from 20 Hertz to 20,000 Hertz with no more than 0.5% total harmonic distortion.

The SX-636 does have some occasional issues with bad transistors (especially the 2SC1451 transistors on the power amp) and, of course, burnt out lamps. It also does not have a protection relay, and instead, relies upon two fuses on the back panel. But, these are more for the protection of speakers rather than the amp itself.

The build quality of the mid 1970’s Pioneers stereos was very good. The later SX-X50 series was probably the best but the SX-X3X series is a close second and doesn’t have too many difficult to find proprietary IC’s. It is also very easy to work on which can save you money if you need to have a tech look at it.

Overall, Pioneer’s SX-636 is a great mid-range receiver. If you’re looking for something with a good phono amp to play records or have a small to medium sized room you want to fill with great sounding music then be sure to check out the SX-636.

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12 thoughts on “Pioneer SX-636

  1. Thank you for this write up on the Pioneer SX-636 stereo receiver. In 1974, as a high school kid this was my first ‘true’ audiophile venture into the realm of high-fidelity, along with my friends, each who had purchased and assembled their own high-fidelity stereo systems. [Remember, using the term Hi-Fi is verboten!! Implies a low rent, low quality, cheap, one step above a kids radio, listening device.]

    Along, with the SX-636, I had Electro-Voice floor speakers, a Dual turntable [never use term ‘record player’], Teac reel-to-reel tape deck [wanted a Harmon Karmon at the time, but that was out of my price range]
    {SIGH !!!! ] But all of that has slipped away into the past, that was my childhood.

    Thanks for the walk down memory lane.

    -Dave G.

  2. Thank you for such a good introduction to the SX-636. I just powered up my Dad’s model (which I remember so fondly from childhood) and the tuner still works. Looking forward to enjoying a “real stereo!” I noticed that the volume doesn’t go very high (just about speaking voice level at its highest) when connected to my Onkyo speakers with the copper wires. I wonder if I should try the second speaker inputs or another connection method? Any advice appreciated!

  3. Is this Pioneer sx-636 also manufactured with multi-voltages application? I saw one on ebay with voltage Selector switch at the back of the unit. It’s rated power is 220 watts?
    But other 636 mostly rated for 140 watts only and can only operate on 120 volts.

  4. In 1974, I was 13 years old and my dad bought his first real system. Pioneer SX636 Receiver, Pioneer PL 12D turntable with a Shure M55E cartridge, Technics RS 615 cassette deck, Sony TC377 tape recorder, and Celestion Ditton 44 speakers. That was the loudest 25WPC I ever heard, we had many house parties, with base heavy reggae, it sounded like a modern day 60-80 watt amplifier.

  5. I am now 60 years old and the Pioneer SX636 is coming back to me. I will be sending it to a Los Angeles shop for a full restoration and upgrade, (LED lights, new capacitors, cleaning, etc.), Bluetooth and remote access will be available with a ARCAM CXN unit. The rest of the system will be a Technics SL1500 turntable with Ortofon Red, later to be upgraded to an Ortofon black cartridge, Marantz CD player, and Wharfdale speakers, and a ELAC subwoofer, which will help the receiver.
    My Dad will send me his other stuff, such as the Pioneer PL12D turntable, along with his AR EB101 turntable.

  6. at a crossroad with choices … Pioneer SX-636 or Sansui 1000x or Sansui 800 or Harmam Kardon 330C? Let me know thanks!

  7. Does anyone have the name of a good shop (in the Chicago area, if possible) to service this receiver. I have a friend who has one and it needs service. I can tell, even in the unserviced state, that it is a quality piece of gear. I can only imagine what it would sound like with a thorough service.

  8. I just bought this receiver from my local record store. It sounds great in my small space and I love the feel of the knobs and the blue lit fm meter! I hooked up 2 small Sony speakers, a 5 disc Sony cd player and my Denon turntable.

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