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should i get the sx 636 or sx650 receiver

P

Past Tense

Active Member
these are on the bay for 185 each plus shipping
i like the way they look
the 636 is 100% working but missing the dial glass (looks like no big deal)
the 650 also works but has dirty pots and needs deep cleaning
this is all i can afford right now
the 636 has lower wattage PC
will 10 watts make diffence i have 90db BA A150 speakers
i need help in choosing one
 
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I have every receiver in the SX-*50 lineup, from the entry-level SX-450 to the SX-1250 - EXCEPT the SX-650. The output modules used in the SX-650 are the primary reason. There is now a workaround for replacing those thanks to the efforts of members here on AK, but that increases the cost substantially for really no gain aside from a protection relay and little else. A secondary consideration is that while both units contain devices which have been know to become unstable over time, the SX-650 employed TA7136AP modules which can be replaced with newer versions, but like the output modules, also require additional efforts and parts to retrofit those into the original design.

For anyone who is up for the potential of more involved repair/restoration efforts in the future for an all-silver face and 8-10 WPC output, the 650 might be a consideration.

Instead of the SX-650, I have a shelf full of SX-750s, which solve all those questions. Again, that's just a personal preference.
 
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I bought a junk SX-650 from ebay that looked like it fell from a truck, one side of chassis is even curved from the fall. I've fixed, recapped and retransed it and I can tell you that is is one of my favorite sounding recievers.
I use the same speakers for all receivers I have, SX-580, SX-780, SX-636, SX-737, SX-838, SX-9000, Technics SA-600 and more and I can definitely tell the difference.
It is also a pleasure to work on SX-650.
 
Thanks guys
I went for the 650 the unit needs pots cleaned and I ordered some deoxit d5 from Amazon I already have the cheap contact cleaner
I do plan to restore it soon
It doesn't have any scratches on front but has scratch on top metal and of coarse cab needs work
I dug out my ct f500 cassette deck and replaced 3 out of 5 belts and my pl516 turntable still need to get a new cart and belt for it
 
Past Tense said:
Thanks guys
I went for the 650 the unit needs pots cleaned and I ordered some deoxit d5 from Amazon I already have the cheap contact cleaner
I do plan to restore it soon
It doesn't have any scratches on front but has scratch on top metal and of coarse cab needs work
I dug out my ct f500 cassette deck and replaced 3 out of 5 belts and my pl516 turntable still need to get a new cart and belt for it
Click to expand...

D5 is for switches. Don't use it on pots, use F5.
 
The SX-650 for sure. I restore them all the time...VERY easy ...and sound is amazing. And yes, the Output modules are oddballs BUT 1) I havent had one fail though they can and 2) They do have a replacement for them now

And BTW...they are NOT 10WPC. MUCH MORE...picture below is one I recently restored
Pioneer SX-650 | Classic Receivers

Specifications
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: 197620221022_031334154_iOS.jpg
 
I knew that it was 35 wpc
What I meant is the 636 is 10 watt less thanks for the info9
I will need to find a tech that can recap it here in rochester ny will have to wait till after the holidays
There's a scratch on the top of the metal and cabinet that I will work 2on
But anyway I haven't got it yet

.
 
Post a photo of the scratches on top of the front panel. There may be ways to improve the appearance.
 
If the pots are just dirty, (no corrosion), the CRC Electronic Cleaner will work. Just be sure to follow it up with a plastic-safe lubricant. In the CRC line, the 2-26 works well.

download (5).jpeg
 
I have had both and the SX-650 has three negatives for me. The power switch tied to the speaker selector switch. Then the output power packs are rare to impossible to source, or use to be. Lastly the super cheap "wood" vinyl clad cabinet.

The SX-650 might have a few more watts of power.
Looks like 10 over all would this make up for the negatives mentioned?

The SX-650 does perform well. I used one for years out in the garage with little maintenance.

The SX-636's I didn't keep around long. Having a SX1010 SX939 SX850 .... didn't make sense.
 
satellite65 said:
D5 is for switches. Don't use it on pots, use F5.
Click to expand...

Use DN5 for pots, followed by F100 if you like.

The 636 is much easier and cheaper to work on than the 650, and being simpler, is more reliable. However, be prepared to replace a lot of small signal transistors in one.
636 has discreet output transistors. 650 has STK modules. It is absolutely crucial that you pull the STK modules from the heat sink, clean them, and apply new thermal compound before using the unit.
The 650 has a speaker relay to crud up, the 636 doesn't.
650 has more power, and sounds like it. 636 is more attractive (IMCO), and sounds very good.
Either way, be prepared to spend some $$ whichever one you get. There is no such thing as an unrestored vintage piece that works 100%.
 
+1

If you're going to buy vintage, plan on:

1. Paying someone to fix/repair/restore the piece when problems arise.

-or-

2. Plan on doing, (or learning how to do), the repairs yourself.

The 650 is close to 50 years old and it's a testament to Pioneer's build quality at that time. Definately worth the effort.
:beerchug:
 
Here are the pics of the scratches
And seller didn't tell me about the chips on top
 

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