Here is a list of changes I did to the amp:
Plate Resistor Mod:
Replaced R6 & R7 (100k Plate Resistors) With Vintage Specs. 220K ½ Watt Carbon Comp Resistors
Top boost channel Mod to tame excessive treble:
Replaced C13 with a 68pf cap.
Pre-amp gain mod:
Jumpered R49 to get more Pre-amp gain on the "Normal" channel.
Brilliant switch mod:
Added a permanent 68pf cap to the circuit and replace C12 (220pf) with a 68pf cap to obtain switching from 68pf to 136pf values.
C10 470pf 500v silver mica
C11 .047uf Mallory
C14 .022uf Mallory
C15 .022uf Mallory
C16 56pf 500v silver mica
C17 .1uf Mallory
C18 .1uf Mallory
C19 .1uf Mallory
C20 .1uf Mallory
C23 .0047uf Mallory
Power tube mods:
Changed the 100 ohm screen resistors on the output tubes to 470 ohm, and the 1.2k grid resistors to 2.2k. This helps the amp run cooler and more stable.
Replaced R18 with a 28K ½ Watt Metal Film Resistor.
Added a 470K resistor across lugs 1 and 3 of the reverb drive switch.
Replace OEM Pan with Accutronics pan # 9EB2C1B.
There is also a Tremolo mod that speeds up the Tremolo which I did not do because I like a slow Tremolo.
I also did not change the power and output transformers for upgraded ones because I don't think the tonal gain is worth the cost. My AC30CC came with all JJ brand tubes, they sound just fine.
If you want more details of the mods, Google "Lyle Caldwell AC30cc mods". You'll get lots of hits, it's all over the Internet.