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
sean
6,231 posts
 
I agree with RC. Nuff said... Sean
>
binaural
18 posts
 
Excuse me while I go knock on a piece of wood... OK, that done, I've had wonderful luck leaving my preamp on 'all the time' for nearly a decade. I only power it down for moving or cleaning. Oh, did I mention that I've never had to replace the tubes?!? Way to go Michael Elliott (Counterpoint).
marakanetz's avatar
marakanetz
5,473 posts
 
24/7 operation definitely shortens tubes' life in ALL cases.
Moreover your electricity bill grows.

Unswitching tube components after the tubes rich the steady state(10...15min for preamps and other small signal tube components) will NOT shorten the tubes' life.

Switching back tube components after they've riched an initial state(5...7min for preamps and other small signal tube components) will NOT shorten the tubes' life.

Under the initial state we should define the state when no emission of electrons takes place from cathode i.e. the tube is literally cold including the tube base if such exists.

The positive issue living 24/7 tube component operation is that your system is always ready to play. Some components improve the sound during staying unoperated for another hour after the steady state but only on couple of small quantums of relative improvement(Someone recently posted a thread about quantum-tweaking units:^)-).

The power tube amps can be maintained the same way with 1.5x...2x longer intervals(think logically!).

These thoughts shared with me by VTL customer service and they realy work.

IMHO it doesn't make a sence to live components overnight without work.
I often call the babysitter to turn my tube-rig on(just only one button) when I finish working so I can come and listen.
dopogue
1,773 posts
 
My Moscode Super-It (3 l2AX7s) came with explicit instructions to leave it powered on at all times. To reinforce this, it doesn't even have an on-off switch. Harvey Rosenberg claimed the tubes would last for a minimum of 3 years left on 24/7. I've had it for over l5 years, have never blown a tube, and have replaced them every once in a while out of some feeling that I ought to, but the pulls have always tested good. As they say, YMMV.
karls
332 posts
 
Small-signal tubes are usually rated for about a 10,000 hour lifespan, give or take. They will often last a lot longer, but they start to get noisier and sonic quality does start to degrade. So if you leave your preamp on 24/7, 10,000 hours is reached in a little over a year. If you are willing to retube your preamp every year, then no problem. Otherwise, turn it off when not playing, and you'll probably get 10 years or more of tube life. Power amps are even worse, with output tube life of a few thousand hours and much higher replacement costs.
More to discover