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.
