Polytone 215-700 Custom Bass Amp - Need Wiring Diagram and/or Owner's Manual

[mikelazich]

Hi,

This an old 2 x 15" spkr combo amp circa 70's.

Would appreciate help if you have a schematic for it and/or an owner's manual.

Polytone is of no help.

Thank you.

[52 Bill]

I've seen a few oddball Polytones that were basically custom ordered units that were made up from their standard preamps and power amps. Have you compared the amp with any of the existing schematics out there?

[mikelazich]

First, thanks for the suggestion.

An amp like this one was used by the late Al McKibbon, who was a well known jazz and west coast studio bassist who played with many of the jazz greats along with a long line of studio/session credits for songs which we all have us have heard.

This amp appears to be one of the company's very early units and not a "special order" amp as I have seen others in searching the net for a wiring diagram including Al McKibbons identical amp. The company apparently made a guitar variant as well, because I've seen a picture of one on the net that has a reverb built in as well.

I am not electronically sophisticated enough to read a wiring diagram, nor do the repairs myself. I understand a bit, but I would not try to repair it myself with the limited knowledge I have. What I was hoping to do was find the wiring diagram and bring it to a repair person I know to fix it once I have the diagram.

At present the volume is very low and there is a "hum", which I do know means it needs at least capacitors.

[52 Bill]

The front panel of the ones that I found on the web look like the standard Polytone 100 series panels, but in a front position. I'd still guess that the amps are made up from the same basic circuits as the other amps from that time period.

I would think that an experienced tech, especially one that knows Polytones, would be able to service the amp even without service info. A bad cap is a bad cap.

[mikelazich]

Polytone Schematic Needed for 215-700 Custom Bass Amp

Thanks for the suggestion of trying to find a Polytone 100 schematic.

I would guess "100" refers to a hundred watt RMS amp. The amp inside does not appear to be a 100 watt amp from my ignorant eye as I'm not sophisiticated, but compared to solid state amps I've seen in the past. As I don't know what I'm doing, I could be wrong and it could well be 100 watt amp.

You're right a cap issue would be simple to address for an experienced tech, however I'm trying to cover all the bases before I bring the amp to the tech in the event it has other issues as I bought it used with the known problems.

The tech I use is not a guitar amp tech or a musician. He mainly services audio tube gear and has no experience with Polytones. His only experience with guitar amps is solely from the various amps I've had him repair over the years.

Thanks again.

[J M Fahey]

I suggest you google around a little, download whatever Polytone schematics you find, there's usually only 2 or 3 versions which cover 99% of them, print them and give the whole package to your friend.
From what I know about Polytones, they use the same building blocks everywhere, even in they PA amps which "should" be different to Guitar/Bass amps, and just modify cabinet and speaker options.
Nothing bad about that, may I add.
And from a servicing point of view, as here, consistency is a *big* help.

That said, make sure your friendd is comfortable working with SS gear; many "tube amps only" techs are not.
In that case, maybe a seemingly unrelated one, such as one who regularly services, say, TVs, VCRs, or industrial equipment might be a better option.