Improving the Fender Tonemaster Gain Channel? Grid Resistor location?

[louderock]

Looking to tinker with my Tonemaster to smooth out the gain channel a bit. It's was too bright and buzzy. I read something about the location of the grid resistors and how the wires are bound with some other wiring that could cause oscillation. Not sure I totally understand all of this so any additional info would be appreciated. Also, is there a bright cap in the amp? Should I clip it?

Apparently there is no NFB loop. Would this contribute to the buzziness? How difficult would it be to add one? I like the clean channel the way it is and don't necessarily want to mod it.

Schematic:

http://www.blueguitar.org/new/schem/fender/tonemstr.jpg

[TweeDLX]

You could put a 500-1000pf snubber across R65 to tame the highs a bit. Adding an NFB loop would affect both channels, but it would go from the speaker tap through a resitor (you add it) to the junction of R29/C33, and then through another resistor added by you to ground. Typical values in Fender amps are 100 ohms (R29/C33 to ground) and 820 ohms (R29/C33 to the speaker tap). Not having an NFB loop does add a lot of grit/treble.

[louderock]

So adding a NFB loop would decrease the gain level and brightness of both channels??

[TweeDLX]

Yes. I didn't see a bright cap on your amp (probably because it has no NFB), so that's a non-issue. Look at some traditional Fender Black Face layouts, and you'll see the resistors I described. Below is a pic of a Fender Vibrolux Reverb with the NFB resistors marked in Green and purple. Notice the blue wire goes to the extension speaker tap.
http://i274.photobucket.com/albums/jj257/paintrdude/Amps/NFBloop.png