svt classic bias. quiet hum one bias led is dim

[ballison]

Hey guys, I just bought an svt classic and didnt notice the quiet hum (which is NOT affected by either the gain or master volume) and looking on the back only the left bias led is green. the right one, its green but significantly dimmer moving the bias control around, it either goes to red, dim, or nothing at all.

Im pretty sure the left bias controls the back 3 6550's and the right bias controls the front 3 6550's correct? I switched the front to the back and no change. exact same sound, exact same led reaction.

also, both of the red led's come on when signal is present. im pretty sure thats normal behavior but since Im new to the tube thing I thought Id mention it.

I will take this in to a tech, but I just wanted to have an idea of what the problem could be before I take it in.

thanks guys!

[kranahan]

When my bias lights went out, I replaced my driver tubes and it works perfectly now! I would definitely give that a try.