Snap Crackle Pop in my 5F2A

[KingCameron]

Hey guys,
I've built a couple fo 5F2As that are absolute tone gods....the only problem is that they occasionally crackle and hiss (not during every operation)
When the crackling starts, it doesn't seem to go away during that operation. Even after a couple of Fonzie whacks to the top of the amp.
Other times the amps operate perfectly through all volume settings.
I have changed tubes, no affect.

Any ideas on what to look at first?

Thanks!

[tubeswell]

I had this in one channel with the 5E3 I recently built (amongst other troubeshooting I had to do at first). A slightly-varying white-hissing noise started a few weeks after I finished it. At first the noise was intermittent, and I thought 'well f*ck its just the character of the amp' - then later it was present all the time, even if there was no input cable plugged in. After changing the preamp tubes (which fixed other problems), I still had this hiss that would only manifest in the 'guitar' channel (it went away when I turned the guitar vol down and wasn't present in the mic channel, so I figured it was before the vol control in the guitar channel). I thought it was a leaky coupling cap in that channel at first, so I unhooked the vol pot end and checked it for DC and nothing, then I measured the carbon comp plate resistors and the one in the guitar channel was 125k - it had drifted (probably through bad soldering on my part). Even though I thought it was probably within the ball park, I decided what the heck and changed it. When I went to unsolder it to replace it the thing fell to bits as I was taking it off of the board. When I put a fresh one in the noise was gone (and the new resistor, having been more carefully soldered in, measured up right). Carbon comp resistors can't take much heat when you're soldering them in. I'm not saying you've got bad plate resistor(s) (I don't even know what resistors you've got in there) - its just a (little) true story. If the problem persists, you could try changing your plate resistors to higher wattage resistors, or even metal film resistors (if you haven't already)

[hollisdevillo]

is it all three of those? or just a pop? or clicks? are they steady, or quite random? i had an amp i was fixing and if the chassis screws were too tight, then it would compress a bit and make a few wires touch making it click. it could also be a bad ground on your input jack connection. it will keep ungrounding and regrounding creating these clicks.

[txstrat]

I had this happening in one of my amps when it was getting hot. Turned out to be a bad cathode resistor solder joint.