The highest I can bias is (a very low number). Whats wrong?
You could have weak tubes, but usually the problem is bad screen resistors (R61, R62) which aren’t allowing your tubes to draw enough current. Always check the tubes first! This seems to be fairly common. Bad screen resistors are usually a sign of bad tubes, so be prepared to change your tubes within the next month. You’ll occasionally hear of Hot Rod owners complaining about a nasty distortion and a dramatic “loss of volume.” This is sometimes their problem. Replace your power tubes, and any toasted resistors and the amp should work fine again. Appropriate resistors can be obtained from Mouser, part # 283-1.0K.
