Tube Preamp.. On or Off?

I know this in an old topic, but even the owner's manual says to turn it all the way off (power supply too) if you are not going to use it in the next 24 hours.

Sonic Frontiers preamps are designed to be left in standby. It's a nice feature, why not use it?

I have a CJ Premiere 17ls. I leave it in stand-by mode or I turn it off if I am not going to be listening for awhile. Leaving it on will shorten the life of the tubes as you have found out.

I have a CJ PV12L. I used to leave it on all the time. It needed to be on at least two days to sound its best. But the tubes kept going out every few months, and it began to get expensive. Now I just leave it off until I want to listen. I know I'm not getting the very "best" out of it, but my tubes have now lasted nearly a year with no signs of sluffing off. If you want the best from your system, yes, leave it on. But you will shorten the lifespan of the equipment and the tubes. Happy listening.

My Anthem pre2L does not have a standby mode, but upon turn on it does go into a standby phase for 30sec and then I pwr up my Anthem 1. I myself do not leave my pre on all the time I just wait about a hour before I settle down to listen. The pwr amp stays off.

I've struggled with the same issue on a variety of tube gear. I would not leave any tube gear on 24/7, even though it probably sounds better to do so in many cases. While small signal valves don't wear as fast as power tubes, they do eventually consume themselves if left on. Really good matched NOS small signal tubes are just too expensive anymore to permit this practice, IMHO. The Line series at least has standby mode. Standby mode keeps the cathode heated only, which reduces wear over full emission operation. Standby will use up a tube, albeit at a reduced rate. The advantage of standby is elimination of the power up surge which stresses tubes. Most tubes fail during a power up. My approach has been where I'm not going to listen for two days or longer, I power down completely. Otherwise, the wear of two days' standby is likely less detrimental than the stress of power up. For equipment without standby mode (and for all power amps), I power it down if I won't be listening any more that day. It all boils down to which factor you choose to compromise - ultimate sound or tube life