so,..i got this old electro harmonix polyphaser on my bench...

[pinkjimiphoton]

and am presently trieing to tinker it back together to help out the friend that owns it.
i'm mostly a hack, and a fuzz box guy, but have built a lot of different units at this point.
anyways, i took it apart and cleaned it, re-seated the clock and transconductance opamp, as they were the only ones socketed. found a bad solder on a big poly cap, and i can hear the envelope filter working, but poorly, same with the phasing. also has one broken wire i'm presently studieing to see where to reconnect it to.
voltages are off, but off about the same universally, so first thing comes to mind on a guitar pedal from 1976 is bad electros. it has a plethora of them in it.
most of what i have on stock is fine value wise, but the voltage is too close... i don't want to trust 16v caps in a 15v circuit.
anyways, it's passing audio... a good thing.
very little effect unless bashing the guitar signal on the input. again...capacitors is my bet, as leaking coupling caps can make a very brittle and crackly distortion.

i know caps are over-rated somewhat and should be able to hold a "surge" voltage...but do you think 16v caps will be sufficient on a 15volt pedal?

trying to fix this cheap for my friend, would rather use what i have on hand than have to make a parts order.

thanks

 

[4pyros]

It would work but may shorten the life of the caps significantly.
What is the power source? Is it regulated?
If not the voltage may rise to values higher than 16 volts especially at turn on.

 

[pinkjimiphoton]

hi 4pyros, this one's from 76, it's an unregulated transformer on board. i'll check again, in passing it looked like about 20v feeding the 7815 chip. i'd imagine it surges to about 30. definitely too hot for 16v caps i'm betting.
the good thing is i've got the envelope working, and the phaser barely. it can't work til i get good caps in it.
i've contacted my friend to see what he wants to do. if he doesn't wanna put the bread into it, i'll probably cherry it out. very groovy little pedal!

 

[4pyros]

You could put two of your 16 volt caps in series to get a 32 volt cap.

 

[pinkjimiphoton]

not really a lot of room to do that; i'd have to parallel them with a resistor too if i did that, wouldn't i? or is that only in tube amps?
i'm gonna see if i have enough 35volt and 50 volt caps kicking around to make it work.
if not, i'll hit the local jobber store and pick stuff up. rather order it, but i don't think he's gonna want to wait that long.
thanks for the advice, tho!

 

[4pyros]

Well it would work for testing to see if you want to go farther with repairs. Good luck.

 

[pinkjimiphoton]

worth a shot...i gotta go check my junk drawer and see what i've got. thanks for the advice.

 

[pinkjimiphoton]

checking in with some of the gurus at diystompboxes, appears the area i'd need the higher voltage caps for i should be fine with what i got, there's only a couple electros in the audio path. thanks for the advice!