I like to change the cabs around with my tube amps and I always turn them off before doing it, but is standby good enough? Or is there still a load on the amp even in standby?
I posed this question to George Alessandro as I was looking to do the same thing with a couple of his amps. He said it was not a problem in any way. Not sure if it's ok for all amps, I'm sure the amp gurus among us could elaborate, but I do it (switch cabs in standby) with my amps all the time without issue.