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Burn-in and Biasing

I just got a new VTL integrated (IT85) tube amp yesterday. Two questions:

BURNIN:
--Is it OK to leave it on, on a low level, overnight and during the day, running constantly? (Hope so! that's what I'm currently doing, but I can turn it off when I get home if I have to)

BIASING:
--The manual says that only a recommended VTL tech should bias the machine. It seems kind of complicated. The person who does the biasing needs to use some kind of digital multimeter equipped with autoranging feature. I guess I wouldn't mind trying it myself, but I have never done this.

The manual recommends that the amp is biased when it first is setup. What are people's opinion on this? Is biasing something I could do myself, with that meter?

TIA....
128x128dennis_the_menace
sean
6,231 posts
 
I agree with "two wheelin' Bob" up above. This is something that you should learn to do if you intend to own / operate a tube based system for any length of time. Keeping track of the bias will also let you know what state the tubes are in, as noticeable shifts in bias are also typically related to shifts in tube performance. If you notice that you have to adjust bias every time you check it, it's time to get some new tubes. This is not to say that the ones in use are "bad", only that they are not as stable as they used to be. They could make for great spares "just in case". Sean
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dennis_the_menace's avatar
dennis_the_menace OP
467 posts
 
Thanks.

Just from your experience, do you usually check the bias when you first buy a piece of equipment, fresh from the factory? I'm going to buy this meter from Radio Shack, and have sent a message to VTL, asking for advice and maybe for a tech person I could have come out to my place and show me "how to", but in the meantime, I'd like to hear some music! You think it's OK to do that while I'm still figuring out how to adjust the bias?

(PS... I re-read the directions; they were actually pretty clear, and I think I could probably figure this out by myself, but I'll still wait to hear from VTL...)
danner
202 posts
 
And be sure not to touch the contacts, there's a lot of juice in a tube amp.
marakanetz's avatar
marakanetz
5,473 posts
 
There is nothing difficult in biasing and it can be done by elementary school graduate.

Open the vtl page and surf through to find biasing instructions. A multimeter is a-must tool so you can get to the RadioShack and buy it.

The logical issue: Why would yuou buy a new amp from the dealer and send it right away to the manufacturer to bias???

Once you turn it into AC you should worm it up for nearly two hours before first playback but still you should check the bias prior.

Burn-in your amp by simply listening and drive the speakers on the different volume levels sometimes on high (if conditions permitting).
gs5556
1,234 posts
 
Leaving the tubes burning all the time will not damage anything except for shortening the life of the tubes. Tube life is (normally) anywhere from 2,000 to 10,000 hours so figure on replacing the tubes at least once a year or as much as 4 times a year for some. Tube amps sound their best, IMO, after they're on for 48 hours.

As for biasing yourself, the only thing I can add is to be mindful of your warranty: it might not cover audiophile-induced shorts.
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