2. amps-preamps
  3. 1017083478

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

I just recently purchased a used VTL 2.5 preamp that I'm using along side with an Adcom home theater processor. I've had to do this because I can't find a processor under $2500 that keeps me happy for two channel music. I'm currently going from the Adcom processor front pre outs, to the processor input on the VTL, then out to the amp inputs. I connect only my CD player and turntable to the VTL, and all video sources to the Adcom.

My wife has become very frustrated with this arrangement because it's much too complicated to figure out what to turn on and off, and which volume to adjust- so I've had to constantly leave the unit on and turn until the volume so it's balanced with the centers and rears. Does anyone know if leaving on constantly (but without passing any signal through) shortens the tube life? The logical answer would be yes, but I'd like to know for sure. Or is there another way that I can feed both the VTL preamp and my processor to the amp input without losing sonic quality (like a very high quality Y connector)?

Any advice would be appreciated. I know the easy answer is to get rid of the wife, but that's not an option right now ;)

Thanks!
alouie

Showing 2 responses by rcprince

rcprince
3,080 posts
 
I leave my JP80 on all the time, unless I'm going to be out for an extended time. It may or may not shorten tube life; some believe that the constant starting up of the tubes is more wearing on tubes than leaving them on continuously. If you get good NOS tubes, they will last a considerable time in a well-designed preamp. I recently took out some Tele 12AX7s from my preamp (replaced them with Tele 803Ss, reputed to last even longer) after having them in there for almost two years and they still tested very strong and quiet. Make sure you keep the pre muted, in case of a power outage.
rcprince
3,080 posts
 
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).
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