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Pioneer SX-650

Stereo AM/FM Receiver (1976-78)

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Pioneer SX-650


Trust Pioneer to make your shopping for a stereo receiver as easy as one-two-three.

One: First, determine the amount of power output you need.

Your Pioneer dealer can help with this. If your listening room is of average size, chances are that the Pioneer SX-650 will be just right. It delivers a continuous power output of 35 watts per channel, min RMS at 8 ohms, from 20 to 20,000 Hertz, with no more than 0.3% total harmonic distortion.

Two: Be honest with yourself about the kind of preamplifier control versatility you really need.

The Pioneer SX-650 has click-stop tone controls with center-defeat positions, a high filter, tape-to-tape dubbing and more. But it saves you money by leaving the frills to more expensive units, concentrating Instead on real preamp performance - such as including a super-quiet phono equalizer with +- 0.3dB RIAA precision and a big 200mV overload for wide dynamic range.

Three: Evaluate your AM/FM needs.

Note that the Pioneer SX-650 has high FM sensitivity and selectivity, PLL multiplex for superb stereo separation, and a special IC for AM to more than satisfy your requirements. Trust Pioneer to deliver what you need and then some - one-two-three in the SX-650.


Tuning range: FM, MW

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

Frequency response: 10Hz to 50kHz

Total harmonic distortion: 0.3%

Damping factor: 30

Input sensitivity: 7mV (mic), 2.5mV (MM), 150mV (DIN), 150mV (line)

Signal to noise ratio: 70dB (MM), 90dB (line)

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

Speaker load impedance: 4Ω (minimum)

Semiconductors: 1 x FET, 9 x IC, 21 x transistors, 29 x diodes

Dimensions: 480 x 149 x 371mm

Weight: 13.1kg

Year: 1976


service manual   English -

instruction/owners manual   English -

brochure   English -

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Reviewed Aug 23rd, 2015 by gencoiable

I'm an electronic technician and It was my first vintage receiver repair attempt also first vintage receiver.
I've bought mine as broken. Power ic's and protection relay was missing. After finding missing parts around the world and a full recap and cleaning, I've a brilliant sounding hi-fi receiver except FM. At first FM didn't work. Some fine adjustment later, FM started work as good as a new unit.
I like this wooden case receivers of 70's. They are very well made and vintage look is so beatiful. There is no visible plastic parts on unit.You can just see metal and wood.

If you can replace or recondition some parts on pcb's (like electolytic caps), veneer on wooden case and some rust on metals, this unit nearly sound forever .)

Reviewed Jul 12th, 2015 by anderscastle

If you see one. Buy it!

Had the bigger ones 1250, 1080 1010 and they Sound good, but this sounds just a little bit better. The bigger ones in order for them to Sound good you have to have the volume up a bit and with massive amount of power it get some what tiresome after a while. The 650 rated at 35 rms is not that 'powerfull' but dont get me wrong it carries plenty of punch but the sound is so balanced and you can still make it sound good and still have a conversation without yelling.
But the showstopper in this which i find far superiour than the other receivers is the fm tuner, which is really really good.
So if you find one buy it!

Reviewed Jun 16th, 2015 by tutor turtle

My girlfriend (now wife) bought this Pioneer SX-650 new in 1977. Positioned in the lower-middle of Pioneers late 70's lineup, it was a very good value for the money. Clear, clean with plenty of power, it seems underrated at 35 watts, sounding closer to 50. Smart cut aluminum faceplate and machined knobs makes an impressive statement. Only available in vinyl clad MDF, it can easily be veneered in real wood, which I did in walnut after recapping it this year (2015). Now it looks as good as it sounds. I have bought restored and sold a number of this model averaging ~$250 for my efforts. The price new in 1977 was $160, or $625 in todays $s. Finding one restored for $250 is a bargain in todays world.

Reviewed Jan 04th, 2015 by rsp781s

I recently acquired my SX-650 from a third party. After all these years, it still is in amazing condition and the sound of a true HiFi Receiver is just completely different from modern digital equipment. I would highly recommend this unit. Very well built and the warmth of sound is excellent.

Reviewed Sep 13th, 2014 by leemitchener

very clear treble response exellant sound quality well made jap monster.
go buy one.



660sherry's picture

re: SX-650

If anyone out there could help me I'm trying to find out what's wrong with my sx650 pioneer. The amp works great on every channel except for phono! No sound! It's not the record player I hooked it up to a different amp and it works fine.also plugged a double headed RCA jack into the phono plug touched the other end and nothing still no sound. I have no idea what to do but would love some advice.

re: SX-650

Try swapping left/right cables, does the "dead channel" move? If yes: bad cable or phono cartridge.
Then try contact cleaner (Deoxit is best).
Unplug everything, remove covers, do this in a place where the dirty cleaner can drain away without staining tables or carpets.
Rotate controls while spraying. Follow up with compressed air, no more that 60 psi or so, canned air is the safest bet.
Rotate controls while blowing dry.
If it still doesn't work you need a technician, it is a very simple circuit, 4 or 6 transistors, a dozen caps and resistors, not complicated at all.

re: SX-650

Greetings: I have a Pioneer SX-680 Stereo receiver that I purchased in 1980 that is showing its age. Both the left and right channels sound OK however the audio level is higher on the left channel versus the right with the balance control at mid-range. On occasion I have heard noise on the right channel. I have to set the balance control at about the 3 o-clock position to compensate. Also, the tuning dial does not accurately indicate the the actual station frequency for example 820 AM is at 800 and 98.7 FM is at 96.7. If someone could point me in the right direction I would be grateful in my effort to restore it to peak performance. I have an OPERATORS MANUAL, schematics and a parts list. MUCH THANKS, RUSS

re: SX-650

Dirty contacts are the most common cause of noise and attenuation. Use "Deoxit" contact cleaner in safe place away from delicate surfaces (do this on a work bench) blow dry with compressed air. Limit the air flow to 60 psi or canned air to avoid damaging other components.
The second most common failure in this series is the speaker protection relay having corroded contacts. You could take the relay apart and burnish the contacts, or buy a new one. The pin-out is a common one, the coil is rated at 12volts, again very common.
Pioneer used the same relay in many of their models of the same year. Check the part number to cross-reference, or call Pioneer themselves, they had stock last time I needed one. ~$15 + shipping.
Tuning accuracy is as simple as moving the set point on the needle (where it is glued on the string) Do this only if the FM and AM are off by a similar amount and in the same direction. If one band is "on station" and the other band is "off station" it is capacitor drift. Recapping may help, it may need to be re-alined after. This job is best left to a technician with the proper equipment.
I hope this helps.

Jim Libert's picture

re: SX-650

New Caps throughout the entire receiver (electrolytics) and the tuning string has probably migrated. You can remove the cover and carefully move the pointer to the indicated position. I currently have a Pioneer SX 626 that needs to have the tuning string replaced. I weakened it when I was soldering and it broke. Shouldn't be too hard to replace with some 40 pound Braided Nylon Fishing line.

My SX 650 needs TLC

Well it's finally time for a tune-up, I've had this receiver since 2003; it's the perfect compliment to my Sony PS-X3 TT. It's experiencing hum when turned on, the left speaker channel shorts out and the light bulb, of course, is burned out; incredibly it still sounds great! I'm grateful to have found this manual though before I take her to the shop I'll know a little bit more about this dependable receiver that I hope to own for a few more decades.


It's so good to have copies of this information again. My wife and I bought an SX-650 in 1977 and it's still going strong, currently powering a 4 speaker system in our garage (it's nice to have music or a ball game when working outside or relaxing in the driveway). Since the garage is built into the lower level of the house with a bedroom over it, it makes a great listening enclosure for the entire system.

new lights

I have owned a SX 650 for many years. I bought it from our loacal recycle centre - YES someone had dumped it ! Silly man. I paid something like £3.50 for this beauty. 18 years later and "she" is still going strong. However the lights for the Dial had died years ago (as they are only little bulbs)
I have replaced them with super bright Blue LEDs with the 7.5v ac tap running through an AC to DC circuit I found in an old PSU. The result is smooth, brilliant blue light, instead of dull light as before !
Thankyou for the scematic it helped find the voltage used on the lamp stage.

Balance control

bougth SX650 in '78, original owner. problem is balance clicks off-on. speakers are pioneer, had them serviced several times; I was told the resistor used aren't made anymore for the SX650, help with this. Also would likr copy of owners manuel.


This is great help! Thanks to the uploader and to hifiengine!

SX650 Manual

Thanks to who ever uploaded the manual

I just picked this receiver

I just picked this receiver up without the owners manual. This download covers a few questions I had.
Thank you who ever uploaded this document!!

Great help!

Thank you for this manual! I got this dusty but working Pioneer SX650 and wanted to "modernize" it by reconfiguring its tuning circuit, power stage, etc. Obviously I needed the schematics to tap into this thing. I searched online without much hope. But you guys surprised me! This is great help! Thanks!


Also want to thank whomever provided the SX-650.

Thank you

Thank you to who ever uploaded this manual.

operating instructions

i am trying to find owners manual for pioneer sx-650 and sx-680. all i can find are service manuals and i dont need them--thank you-- terry


Me too! I'm trying to find an owner's manual for a SX-727 that I can download and printout.

This website is not affiliated with or sponsored by Pioneer. To purchase SX-650 spares or accessories, please contact the company via their website or visit an authorised retailer.