Joule Eletra LA 100 MKIII

One doesn't generally bias tubes in a preamp.

As Truman says, there is nothing to balance in the Joule
preamp. What you do is buy tubes that are tested forn noise
and matched. I would call Jud and have him discuss the
issue. It sounds like you just got the preamp? If I remember
correctly, the preamp needs a 5751 and 6350 tube, and a pair
of OA2 and 6EM7 - I would recommend sticking with Jud for
tubes as long as he is involved and selling to the market.

There is a bias setting in the preamp for the driver tubes (I believe batteries are involved) and the manual discusses how the bias is set at the factory. IIRC the manual also states that changing the bias can allow one to tailor the sound a bit. Jud sent me the instructions for biasing a while back when I owned the LA-100 MkIII. I may still have them. I will warn you in advance they are a bit complicated and requires two volt meters to be used simultaneously. Send me an email and I will see what I can do.

I stand corrected. I knew there was battery bias in my LA150, but I thought that was just a matter of replacing the battery at some point. Sorry for my misleading comments.