Tubes vs Solid State

Wolf, I have actually done that. The covers on the amps I happen to be using at a given time always have the screws removed. It takes about a month to settle down a particular amp and get it's bias and it's offset optimized. After that it needs to be checked regularly. Contrary to popular belief, ss amps are by no means maintenance free. Once you've got it 'actually' running optimally, this whole thing about IM, TIM, brightness, etc. becomes moot. The key is channel balance within the amp. You either have it or you don't. When you do, that so-called brightness becomes attenuated, the amp becomes very linear sounding, and you have an actual dimensional sound stage. But I'm a vintage guy. Can't speak about class D or switch-mode amps.

Wolf. I had a neighbor once who was an EE professor, he told me you can't build a meter fast enough to show what an amps really doing.

Wolf- I have started to see people changing OP amps like tube rollers, and further people with the means often have their gear modded with different "better" capacitors and the like. It happens that tubes are easy to change in most circumstances. As you said tubes are more fun I agree, part of that fun has been rolling some of the best tubes ever made into my gear.

The meters on my Squeezebox tell the input level balance in an obvious visual format, and it might be possible to correlate this to amp output if I cared about that. I do understand there are some who tinker with SS amp innards, but for instant gratification fans tube rolling is hard to beat.

Schubert, you only need to care about what an amp is doing on average. So the meter doesn't have to be fast, just accurate. However, my position that you must do final adjustments while listening doesn't cease to be valid, for other reasons. But bridged monos are a whole other ball game. Here you have no choice but to rely on your instruments until you finally 'hit' it. I've tried using just right channels on both amps in stereo, matching them, and then matching left to right in each amp. That doesn't work because bias is thermally influenced and the unused left channel runs cool initially, influencing the overall temp of the amp differently than when it's being matched to it's respective right channel. These temperatures are critical and no two identical amps behave identically, just as no two identical channels of a stereo amp behave identically.