Triple Gang Pot sources or options

[sonicmojo]

I'm trying to find a triple gang 3x25K linear pot for a busted SUNN amplifier. It doesn't exist at conventional supply sources from what I can see. Does someone know a source for such an item? Maybe I can splice together something out of single or dual gang pots.....or something.

Thanks for any tips!

[Stevem]

What is busted with the pot stack, as many times you can take them apart and install new donor sections from other new pots!

[Leo_Gnardo]

What is busted with the pot stack, as many times you can take them apart and install new donor sections from other new pots!

True 'nuff, I just rescued a master volume an a Mesa MkIV by taking it apart, cleaning carbon track & wiper & ring. The real problem was corrosion on the metal wiper ring & it wasn't responding to the usual Caig sprays. And on a Peavey, swapped in a 10K linear track from a donor pot to fix an otherwise nonobtainium CTS. Worth a try on your triple-decker. IF you can get it apart.

[sluckey]

In case you can't find a replacement or repair that pot...

That pot is the speed control for the tremolo. You can replace two of the 'gangs' with two 25K resistors and just use a single gang 25K pot like most phase shift oscillator circuits. The frequency range may shift a bit but you can juggle the three caps to get the range you want.

Or, if checking the pot shows that only one section is bad, just replace that section with a 25K resistor.

[xtian]

Adding one more tip to those above. You can bend the wiper arm a bit so that the wiper traces a new path on the carbon tracks.

[sonicmojo]

What is busted with the pot stack, as many times you can take them apart and install new donor sections from other new pots!

You may laugh when you see this but I got the amp as chassis only (no transformers) and it has been exposed to elements for who knows how long. This is kind of a challenge to self project to see if I can restore it. I'll probably strip the entire thing and really go to town on cleaning the chassis and individual parts, salvaging where possible. SUNN used a lot of rivets so I'll have to drill all those out! The pot possibly will work okay with a good cleaning but I've so far just been going through it trying to identify parts that I might want to replace/repair. I am getting mostly decent meter readings after a little de-oxing.

[Structo]

Careful with the DeOxit.

It can damage some pots, but probably not these vintage pots.

That is great you are trying to restore that amp.

Sunn amps where made about 40 miles north of me and a lot of big name acts used Sunn amps in the 70's and 80's.

Bob, the owner of Eurotubes is a fan and has interviewed the owner and designer of SunnAmps Conrad Sundholm.
http://www.eurotubes.com/store/pc/sunn%20amp%20page.htm

[sonicmojo]

Good to know about deoxit. I've seen that crazy Eurotubes collection! I recently discovered the apparent SUNN resurgence when I fixed a Solarus for a local shop and then this chassis popped up on eBay as if by fate. Fortunately I am able to borrow the other one for reference. It is the exact same 40W EL34 model. Mines a '68 and the nice clean one is a '69.

[Stevem]

I have a Fender amp that had been out side for a year and it had tons of crap in it and rusted even more than yours and to jaw dropping amazement all the pots where and or cleaned up fine!

[sonicmojo]

Thanks for the encouragement! I removed the faceplate and pulled the pots back and went to town with a dremel brush. Hopefully it is mostly superficial. I'll take my time and get it right.

[sonicmojo]

Success! Got it working well with new transformers, caps, etc, etc.. The pots are all okay. I'm still experimenting with the optotrem module. I have to make my own out of an LED and photoresistor as the original part is unobtainable.