I have a "legend super lead 100" guitar amp from
the 1980s. Very cool looking amp, solid
finger-jointed oak cabinet. It has a 12ax7 preamp
that sounds pretty good. But the "color gain"
doesn't work right. At 0 you don't get any sound.
At higher settings, the amp works but no "color"
occurs (ie clipping @ CR1/CR2). I'm in a little
over my head here. The color gain is not wired
exactly according to the schematic (problem, or
post-production tweak?).

Schematic (149kb):
http://www.telusplanet.net/public/beaumac/preamp.gif

Actual factory wiring (24kb):
http://www.telusplanet.net/public/beaumac/actual.gif

The actual wiring prevents the "shorting" of R10
@CCW thereby preventing significant "color"(right?).

R9 goes to ground @full CCW. This acts as a volume
control on low settings, which it shouldn't do
(signal at the grid of V1(2) to ground). Is this
just bad design?

Would this work instead? Do I need to worry about
current flow at the grid V1(2)?
http://www.telusplanet.net/public/beaumac/new.gif

Any help appreciated.