Hmmm caute, nenajde sa tu nejaky schopny handmade letovac z BA a okolia (nejde mi o niekoho kto drzal pajku 2krat) , ktory by sa bol schopny vyjadrit k nasledovnej uprave? Ide mi o mierny upgrade mojho peavey 6505+, nasiel som na nete post od jedneho typka a zneje to nasledovne: (pripadne ci sa najde niekto kto by to vedel spravit, za cca kolko a ci to ma naozaj nejaky zmysel takyto zasah) dik:
Another issue regular purchasers managed to have was the lack of balls when the gain was brought down to, say 5-6. You'll need to replace the bypass cap on V1 with a 1.uF+ cap (It's .047 stock, I believe.). This will add nuts to your tone when it's around 5 and increase the gain a bit. The bypass cap on my amp is 2.2uF, nice and thick.
If you really want more distortion and a thicker low end, replace the cathode resistor on V1 (2k7) with a 1k-2k resistor. Lowering the value will take you where you need to go.
Bring down the bright! Replacing the 470pF ceramic cap will bring down the brightness of an amp, especially if there is a 150pF cap in parallel! My amp has a 90pF cap (240pF total), just to give you an idea of how much taming amps may require.
In the tone stack, right up front is an 82K resistor that sort of controls the lower mid-range frequencies (Making it sound a bit cloudy). I added a 100k pot from an old boss pedal (the pot is small and square) so that I can lower the value accordingly from the front of the amp. To tighten up the tone a bit and take a bit of the "flabby" mids out, lowering this value helps a lot.