What is bias a tube amp ? Is it difficult?

Well made amps don't require biasing very often, and it's a good idea not to go crazy with this simply because frequent biasing will prematurely wear out the pots.

The CJ and Rogue amps I have are basically set it and forget it. I check the bias once every six months or so on the Cronus but with the CJ I haven't had to touch the bias for almost year now. And I am running Winged C Svetlana EL34s in each.

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!

The Rogue M-150's I'm using hold bias very well. As others have mentioned biasing is really easy and not something that needs to be done very often. As I understand it, having a way to bias the tubes in the system can save you money in not necessarily needing to purchase well matched sets. I also like the option of running some tubes a bit warmer or cooler to tweak the sound.