i did a fairly simple mod to my homebrew 100 watt
plexi...the 3 power resistors WERE (from end towards
pre-amp), 20K,10K,10K...so i replaced the 20K with
another 10K so that all the power resistors are now
10K's....this alone, raised B+ to V1,V2, (i believe V3
too)....i matched up a pair of 390k ohm "splitter
resistors" on the front end and replaced the stock
470k's...this change gave the amp a sweet-as-hell
sparkle & spank thing!....love it....real responsive to
pick attack, harmonics, etc...

I did that same mod. (changed to a 4.7K-ohm
recommended by Trace A.) to my 2204. Great
results!!!
It really brings out the tone of my single coils.

If your amp is a master volume type locate V1B (1st
preamp tube) and track either pin #3 or pin#8 (often in
the '70's the wiring was a bit different). You will find a
10K 1/2W resistor. Change this to a 4.7K and you
should be pleasantly surprised.
This mod is easily reversible, just keep that original
10K resistor handy...
 
I don't have schems here, but I think this resistor is R1
or R15 (I am decaffeinated and need a few more
cups!!!) This resistor was located at the end, closest to
V1B of the preamp circuit board on my '84 2204).

On the board the silk screened value is "R6"...just
remove the 10K and pop in the 4.7K and you're all set!
   
 
Trace


Easier way is to cherry pick a low value 10k resistor
and tack it on in parallel to the existing resistor. Faster
than yanking the board and you don't have to sweat
lifting a trace.
 
Carl Z
http://www.summitamps.com

jim, those would be the 2 mixer resistors on V2
grid....(the one DOES have a 470 pf across it)...adds a
shit load of "snap"