Always turn your amp on last and off first. And I'd use the volume control on your preamp it's likely better quality then any gain pots or attenuators on an amp. Air Tight still makes amps with them and I'm sure a few other manufacturers do.
Amplifier gain settings - what do they do?
gain settings I see on a tube amplifier seem like a good thing.
Should I be adjusting these while the sound is playing and what should I be hearing when I make the adjustments. Why don't all amplifiers come with gain settings?
Also, which do i turn on first the tube pre-amplifier or the tube amplifier?