Hi all. I put a JJ 5751 into my Champion 600, which I really like the sound of and helped to tame some of the gain and overdrive obtained by bypassing the tone and negative feedback loop to a happy (loud!) medium. However, the tube seems to have a sympathetic rattle/glass-and-metal tinkling sound when I hit certain notes (d sharp, iirc); is this a flaw in the tube, or is this typical? Crank it up until it doesn't bother me, or replace? I've chopsticked it, and it's not microphonic.