I turned on my Dark Terror and plugged my Lester in to see how the stock JJ12ax7s preamp tubes could be induced into fizz (just as an exercise). I can do it just by lowering volume and running the gain knob up, up, up. Boosting the volume to the db level that's comfortable to the situation and room size, I tweak the gain down, down, down, until I hear no fuzz, but still have some room left to lower or raise volume with just my guitar's volume knobs.
This I've found, takes some practice of course, but also helps if you have a clear mind and a “target” tone kept in your mind.....that way you're not constantly twiddling amp and control knobs and getting frustrated. Also keep in mind, my experimet(s) are done with only a reverb pedal. I'm seeking my ideal guitar and amp only tone. Later on, if needed, is when I'll think about augmenting a good tone with some color. I don't swap tubes, because I did research my amp's tone reviews before purchase of the Dark Terror. Besides, I don't figure I can afford testing out a supply of tube types...the cost to return factor is not worth it IMO.
All my initial concerns about too little or too much gain proved to be without merit. There was neither. What I had to get my head around was getting my ears to admit that there naturally should be a substantial tone difference between a Micro Cube and a decent tube amp when the tube amp is turned up and starts to produce that desired tone. This is what results when getting used to a 2watt amp with a 5 1/2” speaker as opposed to a 15-watt tube amp through a V30! The human ear needs adjustment time.
Stratstrangler