Gain Pot Question for DIY Overdrive Tube Pedal

[jh45gun]

Found some plans for a Overdrive Tube Pedal that uses a 12AU7 tube I got most of the parts laying around I got to buy a 3PDT foot switch and a couple of caps and resistors and a led. no big deal there I got the jacks and a lot of them tubes and a socket ect. Should not cost me much to build it but on the pots which has three of them volume tone and gain the volume and tone are a 100K pots which I have a lot of. the gain control is 850K which after doing a search does not seem to be that common so can I just use an other 100 k for the gain? I have a fair supply of 100k pots laying around from a junked PA head and I know that pots like resistors can have a tolerance of up to 20%

[czech-one-2]

Originally Posted by jh45gun

Found some plans for a Overdrive Tube Pedal that uses a 12AU7 tube I got most of the parts laying around I got to buy a 3PDT foot switch and a couple of caps and resistors and a led. no big deal there I got the jacks and a lot of them tubes and a socket ect. Should not cost me much to build it but on the pots which has three of them volume tone and gain the volume and tone are a 100K pots which I have a lot of. the gain control is 850K which after doing a search does not seem to be that common so can I just use an other 100 k for the gain? I have a fair supply of 100k pots laying around from a junked PA head and I know that pots like resistors can have a tolerance of up to 20%

Use a 1MEG for the gain.If you dont have that a 500K should work too.
100k is going to be alot less gain.

[jh45gun]

OK thanks One meg is a lot easier to find than 850K Just looked at the schematic for a 5E3 as I have a clone I built here that I was not satisfied with because the iron came from an old hi fi and I suspect could have been better .So that build has 3 one meg pots along with the 9 pin socket I need. So I will grab one of those pots and about the only thing I need is the switch and a couple of small caps and resistors.