Channel 3 is nothing but glissy harmonics amounting to white noise and no TONE. Things do improve by turning the volume pot on the guitar a few notches, but why would that be an advantage if the fundamental circuit doesn't sound great with full on guitar volume? (BTW, Channel 2 is just fine). Looking at the schematic, ( www.webphix.com/schematic%20heaven/www.schematicheaven.com/boogieamps/boogie_nomad100.pdf ) I'm guessing the source of the lack of fundamental tone and all the high frequency content is because of the 680k resistor right in front of the gain pot which forces most of the signal through a 0.002 cap (see pg 4/10 in the pdf). Sorry don't know how to calculate corner frequencies to verify. The rest of the Ch3 circuit looks kind of Marshall-ish, leading to a common tonestack at the back end of the preamp, with a 47k slope resistor. Any suggestions on exactly how to mod this channel to something that has tone? A classic marshall tone would be a good place to start.