Volume pot question

Started by Wild E, February 11, 2010, 08:19:15 PM

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Wild E

I would like to learn how to determine the value of a volume pot or a gain pot between stages. Are there any tutorials I could read that would help?
I recently breadboarded a Fetzer Valve Revisited and didn't have the suggested value volume pot so I've been running it wide open ever since. I haven't even stopped playing long enough to try to tweak the Rd. I would like to box this up but  don't want to lose the sound of "wide open" without having to add a bypass switch.
Can anybody help or point me in the right direction?

aron

If it's a pot that's connected to ground, usually wide open is the value of the resistance between the two outer lugs. For verification, if it's wired as a standard volume pot, the resistance between the wiper and ground is your value.

Wild E

I don't have  pot connected now. it goes from output cap to output jack. That's what I meant by wide open. I want to use a pot that can give me that sound/ drive and still be able to kick it down a bit if I wanted to.

Joe Hart

Well, then "wide open" is a resistance of zero, so wire the pot so that all the way "up" is zero, and going "down" adds more and more resistance. Isn't that how a volume pot usually works?
-Joe Hart

aron

You need a switch or you can use a fender no load pot. At max it takes itself out of the circuit.

Wild E

Thanks for your replies guys, and sorry for such a late response by me.
Joe, I understand what you are saying but the vol pot is connected to ground so even at the lowest setting it puts the total resistance of the pot in parallel to the load so some of the signal will be sent to ground. Maybe if I just left lug 1 disconnected that would work. I might give that a try.
Aron, does that Fender pot remove itself from ground? Are they expensive or hard to find?
Anyway, I think I must've misstated my original question. I was trying to ask how one goes about choosing the value of a volume or gain pot when designing a circuit.