Amp crackle

[rf7]

How do you troubleshoot crackling on the output of an amp? I've got a JCM2000 DSL100 head that's got a crackle after the notes. I don't really see it on a sine wave. If I treat it like distortion and feed a really small signal into it, the output does look shaky and noisy. Is that a symptom of crackling?

[nosaj]

Have you tried different tubes?
Also you could try pulling preamp tubes and see if the crackle disappears, if it does that narrows where to look. What if you wiggle the input jack? or does it happen with no guitar plugged in?

jason

[guitician]

No, if you connect your scopes ground better, you may notice less shaking and noise. Sounds like a speaker may be damaged.