Is it OK to leave a tube preamp on all the time?

If you put a signal through a tube before it reaches operating temperature, you will know it. It sounds HORRIBLE.

Having said that, once you turn on a tube set and the filaments begin to glow, you are ready to operate in well under one minute. Give it a minute just to be sure though. The sound might not be near as good as if you let it idle for a bit longer, but why waste time when you can be listening to tunes ? Try not to "throttle" stone cold tubes though, as this is when you are most likely to do damage to them. That or getting the plates cherry red by overdriving them or having a bias problem.

Keep in mind that this is a broad generalization. Some tube gear might have soft start or circuitry that delays the firing of tubes to minimize in-rush current. Read your manual and go from there. Sean
>

Had a VTL TL 2.5 myself for about two years, and I pretty much left it on all the time except when I knew I was going to be away for a couple of days or more (and then I'd usually turn it off and unplug it). From all that I've heard from VTL and read about their gear, they seem to recommend such an approach. Now I've got a Rogue 99, and they've got a deliberate soft-start circuit to protect the tubes at power up and explicitly suggest that you turn the thing off when you're not using it in order to prolong tube life -- so that's what I do. Which is right? No idea. I've blindly deferred to the fellows who designed the stuff on this one.

Glen, to answer your question -- certainly Yes you should leave your tube rig for at least an hour (especially if you have tubes on the front end) before you will pass the signal. You can clean vinyl or CDs or write bills or have a quality time before you will start listening:)

I must say, that I find M's waiting stand a bit exaggerated, but find RC's and Sean's advice sound. RCprince, you lucky So and So, where did you manage do lay hands on ECC803 teles???!!! Cheers,

Detlof: A friend who also sold me that mother lode of Gold Lion KT88s. He's a contractor, and every now and then he's between jobs and lets a few of his stash go to me. In this case, I had to trade some Tele and Siemens Ccas to get them; if I ever can fix my phono stage in the Jadis, I'll have to go searching for more Ccas, I guess, although the Lamm works incredibly well together with the 80's line stage. I am very surprised at the improvements I've heard since I put the 802S and 803S tubes into the amps and preamp; had very good Tele 12AX and AU7s in there before and these are a clear level better. No wonder they're so sought after.

In answer to Glen's question, in addition to the advice given above, some preamps have auto-muting circuits that will not let the signal through till the unit has stabilized (for example, 6 minutes in my Jadis, another reason I don't like to turn it off!); that gives the tubes time to stabilize and get to operating temperature. I tend to agree with Sean's and Detlof's advice--I leave my Jadis amps in standby to warm up a good 5 minutes to an hour before I listen seriously, but I can and do pass signal at a very low volume level after a few minutes while they're warming up and use it as background music (or, if it's very simple and quiet music, I can listen seriously to it, even at the 1-2 watts the Jadis put out in standby).