Tube Biasing: do I have to?

Uppermidfi - find out! The info is out there on the net somewhere. If you are going to use this arcane technology, it behooves you to learn its ways. There are some very good discussions of biasing output tubes on the FAQ sections of this and other forums.

Bias procedures will vary from amp to amp. You guys would do well to list your specific amp including the model, and or do a search (here, google, and AA) using the amp's name and "bias procedure" (or something of that nature). As already indicated, some amps have an auto-biasing circuitry and do not need to be adjusted with tube swaps. Others which require biasing will require a decent digital volt meter and the basic knowledge of how to use it. The actual procedure, as I said, will vary according to the amp.

If you want your manualy biased amp to run properly and not risk tubes, fuses and or very lackluster performance you do indeed have to bias your output tubes. I would furthermore recommend you check the bias at least once a month or so, and more frequently if you are breaking in brand new tubes.

Marco

The arcane technology john mentioned happens to be the most maturated aspect of high end audio.Study your audio history and you will understand that cd's are still in the thumb SUCKING stage... emphasis on sucking.There are many engineers out there that are slowly realizing that digital cannot offer the many characteristics that a well designed tube stage offer.The young pro audio camp loves digital and that is understandable since they have 30 to 40 less years of analog in their brains than the old fart contingent.Find out the bias #'s that your manufacturer intended for your tubes and if your unit does not autobias then ask the vendor like THE TUBE STORE to bias them for those specs.Good luck

Find out the bias #'s that your manufacturer intended
for your tubes and if your unit does not autobias then ask the vendor like THE
TUBE STORE to bias them for those specs.

HUH?!?! Maybe I'm missing something in what you are suggesting, but how
can a vendor "bias your tubes for you?!" How exactly do you bias
a tube outside of a circuit? You have to place the tube within a circuit and
run current through it in order to bias it, and it has to be the same circuit you
are using the tube within. You cannot bias the tube in one place using one
circuit, send it to another place, insert it into an entirely different circuit with
at different load and expect the bias to be correct. Maybe I've been camping
with the wrong campers. I've stayed clear of you old farts as the snoring
keeps me up at night. Can't stand those young audio pros either cause they
got their music up too loud crankin' tunes I don't click with no more. Maybe
you are referring to tube "matching" which a service a good tube
vendor can and often does provide. But biasing?! Splain that to me, would
ya. Unless you are suggesting he send his entire amplifier, his speakers and
speaker cables to a tube vendor to bias it, which really seems rather
ridiculous as it's a pretty simple procedure to do yourself.

Marco

I stand corrected...indeed I was thinking of tube matching and of course biasing must occur in the equipment.The issue is what the manufacturer recommends as an operating range and then tweaking the tubes with a voltmeter.Simple enough with my VTL amps.