You can add a 250 pf cap, to the drive pot, on the 2nd channel.This will help, get rid of the muddy sound, on the second channel, when using the drive mode. As you raise the level of the drive pot, you will get less effect of the mod. It's just a high pass filter (like on a guitar pot) it works great and is easy to do and reversible. Just a 250pf cap with one end soldered to the far left lug (facing the front looking down at the pot) and the other end of the cap to the middle lug of the pot. You can check it out with some alligator clips first before you solder it.