Searched and couldn't find a solid answer, so apologies if this is covered somewhere else...
Finished up soldering the Meathead Deluxe last night, but didn't get a chance to test it (pesky kids and their bed times...). But I'm not sure what to do about the trimpot...is it a 'tune by ear' thing, or is there a specific target resistance that I would be looking for?
In my opinion it looks like a pot to set the bias of a transistor. Not sure.
But there's no danger in trying to turn it with a screwdriver when everything is powered and you're playing guitar. Just see (ear) what happen.
Some people tell they want to put an external pot, other don't, other tell that it makes no earable difference when they turn it...
I suggest you set it to the middle position and try to turn it slowly while you're playing.
The trimmer adjusts the voltage on Q2 collector. It is what people call a bias control in the Fuzz Face type circuits. Most people will set this to about half the supply voltage, usually around 4.5V, or adjust by ear
Re: DAM Meathead Deluxe - setting the trimpot value?
I just finished setting the trimpot in my Black Acid (very similiar to the Meathead Deluxe ). I did it by ear. With it fully clockwise, the sound gates out so I rolled my guitar volume back and slowly rotated the trimpot back to a spot where it had good cleanup but was balls to the wall with my guitars volume on 10.