What is bias a tube amp ? Is it difficult?

Warren,

My amp designer states that auto-biasing impacts the sound of an amp, and not positively. Nick makes the best sounding electronics I've been privileged to hear, regardless of price, so I believe him. In top level gear manual biasing is probably preferable.

Aside from any degradation caused by unneeded complexities in the circuit, our own ears tend to confirm this from another direction. We readily hear any small changes we make in bias levels, so if the amp were constantly monitoring and adjusting...

Biasing and balancing four power tubes once every 6-8 weeks takes all of 10 minutes. It's no big deal, as others have said. YMMV of course.

Stevecham,

Now that you mention it, I haven't actually *changed* the bias on my amp since I nudged a new quad of Sovtek Reflektors up to full operating level. That was last May or June, and they're running at the same level today and presumably for the forseeable...

I check it out of habit every month or two but, as you say, a well-designed circuit that doesn't overdrive the tubes should remain stable for long periods.

Great. Another thing NOT to worry about. I hate that!