If you're getting fizz creeping in on most amps, you haven't reduced the DC control enough, or there's some other problem. For example, in some installations, I've seen a dual-gang pot used for both Power Scaling and Drive Compensation, which is a bit crude, but shows how much the DC needs to be reduced, i.e. nearly as much as the PS.
Dave, I thought that the improved DC control I fitted to the Deluxe had erradicated any fizziness? Also using the lower gain input? The DC on your amp will stop the fizziness, and when I tried it, both with a guitar and on the scope, it was gone at all but unrealistic volume levels (those where you could barely hear the amp over the strings.)
A problem specific to the Deluxe is it's crude preamp, phase inverter and volume/tone controls which are of course, part of the essential character of the amp, but make it harder to find settings that don't sound mushy, on the unscaled amp, and fizzy on the scaled amp. As you know the volume goes OFF/STILL OFF/ALMOST EVERYTHING/TOO MUCH before it gets to 8 o'clock!
I thought that we'd shifted the small amount of fizziness to well below anyone's realistic practise level?
If it's still a problem, let me know and we'll have a look. :)
