Repairing MXR micro amp for a friend, odd pot value.

[BraindeadAudio]

b10c470? Tried a B10K and sounded terrible. Tried a 500Ck sounded terrible. Put a A500K in there and only gets gain at last 1/4 turn of pot. Tried 500Kb and only distorted at from a little past noon.

Anyone got any ideas? I cant find anything about this pot and Im trying to see if I have anything on hand that would work.

Im sure the A pot with the effect happening last 1/4 turn is from wrong taper.

Thanks in advance!

[electricstorm]

Sounds like you need a Reverse Log taper pot. Can you get ahold of a C500K (Rev. Log. Taper) pot? The 470 value is a UK item, we use 500 values here in the US.

[midwayfair]

Sounds like you need a Reverse Log taper pot.

That's the first thing he tried.

Op, C is the correct pot taper for the microamp. The difference between 470 and 500 is negligible and should only affect the MINIMUM boost. A quick look at the schematic shows that it's the Pin 2 connection to ground -- meaning you decrease resistance to increase the gain. That extra 30K is only affecting the lowest setting on the pot.

Sounds like something else might be wrong if it actually sounded terrible just from using that pot.

[BraindeadAudio]

Thats what I was thinking. The C500K I used, wired both directions just doesnt sound like its supposed to.

I probed the board and everything sounds fine up until the pot.

Looks like Ill be spending a little time on it.

Thnk you for verifying what I was thinking was in fact correct about the POT taper.

Thanks!