Please help me to identify this Pioneer Tube amplifier

[Potato_Head]

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S-l1600 Potato_Head

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Pioneer amplifier from ebay

I have had very limited success in identifying this amplifier.

I did find one on eBay that did not sell recently. Aside from great photos, there was not much detail.

I also found a Pioneer Receiver on the web that looks like they just stacked a tuner on top of the amplifier controls.

Mine has been modified/hacked and has one channel that is not working. I'm in need of a schematic if at all possible. Is there a model number other than Stereomaster?

Thank you

 

[Potato_Head]

This amp has been identified!

It is a 1959 Pioneer SM-c800 amplifier. Dual Monoblock construction with an integrated preamp. 45 watts per channel. Supposedly bridgeable to 90 watts.

All I need now is the missing cage, handles and side plates. An operators manual would be good too!

Michael

 

[BinaryMike]

Thanks for following up. It's an interesting design.

 

[Dandy]

Thanks for following up. It's an interesting design.

Agreed. Could you post a pic from underneath?

 

[quadklipsh]

I will do soon if the OP doesnt . One is coming my way soon. Hoping to have good sound

 

[gadget73]

It sure looks like a quality piece, big transformers, and lots of them. Looks like dual mono config too, very cool.

 

[Potato_Head]

I will do soon if the OP doesnt . One is coming my way soon. Hoping to have good sound

I will be out of town for awhile but will try to post pics from underneath. I have a few pics someplace from other amps. There seems to be some differences between them.

Mine has quite a bit of noise and it has been to two different techs - no success in solving the issue. After getting a schematic I think mine might be wired for 100vac. Might be part of the issue if all of the work that had been done was based on 115 being the correct supply voltage.

M

 

[arts]

I had one of those long ago. It ''kinda'' worked,but in the pre-internet days,nobody knew much about oddballs like these.
It may have been old and rare,but I was actually able to get a schematic from the Pioneer service center.Guy thought I was nuts...

I have to say,the sound was incredibly good,and this was the only amp I have ever seen with cathode-biased EL34s.

Mine was an absolute cosmetic/mechanical disaster; bashed,beaten,rusty. It was complete,but at the time,restoring what was essentially a glorified PA amp (oh,how little did I know!) just wasn't an option.I ended up stripping it,and tossing the chassis.

I still have the OPTs,one power transformer,the filter chokes,driver boards and all of the pots and knobs. I wish I still had the whole thing!

 

[quadklipsh]

I got mine. And its gone to the tech before it came to me.
Id appreciate if schematics or service manuals were seeable

 

[Dswankey]

I got mine. And its gone to the tech before it came to me.
Id appreciate if schematics or service manuals were seeable

Try a search for "Pioneer SM-C800" it took me a few seconds and I found a schematic.

See post #6 in the tread below

https://audiokarma.org/forums/index.php?threads/smc-800.694843/

 

[quadklipsh]

Got it too. Wow. Thanks

 

[tonyg88]

7591 tubes? I bet it sounds nice

 

[Potato_Head]

Try a search for "Pioneer SM-C800" it took me a few seconds and I found a schematic.

See post #6 in the tread below

https://audiokarma.org/forums/index.php?threads/smc-800.694843/

Thanks for doing the digging for me!

 

[Potato_Head]

Here is the schematic again. Maybe having the file named correctly will help other find it in the future!

Note the two power supply connections 117v and 100v. I think that mine is wired to the 100v connection and the techs that have worked on it before did not catch this.

This might be the source of my noise issues, high heat and short tube life. I'll be sending it to a third tech next week to find out for sure.

Aside from the high noise floor, this amp handled my Infinity RS 1.5s with ease.

 

[primosounds]

Mine has been modified/hacked and has one channel that is not working. I'm in need of a schematic if at all possible. Is there a model number other than Stereomaster?

Thank you

You could just copy the working channel. It looks like this amp is a dual mono design. that is 2 mono amps on 1 chassis.

 

[Potato_Head]

You could just copy the working channel. It looks like this amp is a dual mono design. that is 2 mono amps on 1 chassis.

Hello Primo, Thanks.
Part of the issue was in the meter. There was also bad caps, fuse holder and other typical vintage gear issues. I have had the amp for more than two years now. Not using it until I can get it back to a better tech to sort out the remaining issues

 

[quadklipsh]

 

[quadklipsh]

Heres what i got

 

[Potato_Head]

Heres what i got

Very cool. I don't have the cage or rails for mine. I have the meter but it is not working. Is yours back from the tech yet? Is it quiet?

 

[quadklipsh]

Chirps in the right speaker.
Thats all.
Fabulous sound otherwise.
musical and sweet. Details are there and it sounds natural.
Never had a tube amp in my ownership before and this is a keeper.

Now the next plans :
Im going to get

A recap
A paint job.
And metal frame chroming job.
This amp beats my previously owned vintage SS in sonic engagement .