I would not leave a tubed pre on 24/7 and only leave the amp on when you are going to be around it and in general not over night. I do on occasion leave my ss amp on overnight but as a general rule I turn it off. Having said that you should not get a loud hum when leaving the amp on with the pre-amp off. For qualifiers I have a cj tubed pre amp and cj ss amp.
tubed preamp off and ss amp left on?
Why can't I leave my my ss amp turned on with the tubed preamp turned off? Loud hum occurs through speakers with this condition. When I had a ss preamp I could leave the amp powered all the time with the pre off. I would leave all powered up but concerned about the preamp tubes wearing prematurely. Is it a reasonable conclusion that I could leave everything powered on all the time and just change the tubes once per year?