Most tube equipment benefits from being turned off when not in use (saves tube wear and other component deterioration due to excessive heat such as can be generated in tube amps) and a warmup period before serious listening. I've found with my stuff that 30 minutes is plenty. There are amps, pre-amps and DAC's that have a "rest" position which reduce current to a minimum and extend tube life, however, when you think about it if you only have one piece with a rest function you still have to wait for the other stuff to warm up. The are also a few DAC's and pre-amps that place minimal demand on their tubes and can be left on 24/7 (I have and EAR which will give me up to 5 years per set when left on 24/7).
Warm Tubes
I've been reading up on tube pre amps and in particular the ConradJohnsons. In different posts prople have mentioned that the keep their pre on all the time or 1 hour warm-ups, etc. Never have been around tubes audio so evn though it seems obvious it still suprised me. No just flipping on the system. Is a system warm up of an hour or more the rule? Any other nuances with tubed equipment I should be aware of? Thanks, Dave