Alessandro making a funny popping noise

[Sam Evans]

After tube swaps (pre and power), I'm still getting an odd popping/sputtering sound when I play. The amp does not do this when I'm not playing. It kinda reminds me of the sputtering of the Fuzz Factory. I'll ask George in the a.m., but I figured I'd run it by here first to save myself some potential frieght charges.

Sam

[Braciola]

Originally posted by Sam Evans
After tube swaps (pre and power), I'm still getting an odd popping/sputtering sound when I play. The amp does not do this when I'm not playing. It kinda reminds me of the sputtering of the Fuzz Factory. I'll ask George in the a.m., but I figured I'd run it by here first to save myself some potential frieght charges.

Sam
With the amp on, gently wiggle each tube and see if you get the noise you described. It may be something as simple an a dirty tube socket. If you find by wiggling one of the tubes you get the noise, unplug the amp, then try pulling the tube in and out a few times to help clean the connections, a good spray cleaner would'nt hurt in the process.

[Leonc]

I had the same problem with my Bloodhound when I was using all 12AX7s and EL34s. I switched to 12AX7, 12AU7 and 12AT7, as I recall (it was what George recommended to me). Problem solved.

[Dexter Sinister]

In that case, I suspect its blocking distortion. You're probably driving the grid positive. Its a pretty hot circuit, so cutting it back a it should help.

Does the problem occur when you turn down to pretty low levels?

DS

[Sam Evans]

I swapped out 2 of the AX7s for an AT7 and a 5751. Still does it, but not as much. It also does it a lower volumes.

Sam

[johngalt]

Is it tube rectified? I have experienced something like that when a cheap Chinese rectifier was near death.

[Sam Evans]

SS rectifier.

[VaughnC]

It sounds like to me that the amp is just on the brink of breaking into oscillation. Sometimes just rearranging the routing of the internal wiring can correct this condition.

[Sam Evans]

Sorry Leon,

I know I've asked you this before, but is the AX7 in V1, next the AU7, then the AT7?

The problem seems directly related to how hot the guitar is. With a s/c, the problem is gone with lower gain preamp tubes.

I just got the amp back from George. He repalced a scratchy pot, and when the amp was first fired-up it sounded great as usual. That's why this funkiness has me puzzled.

[Leonc]

Sam - man, sorry but I can't remember... :(

[Sam Evans]

No big deal, Leon. I'll run it by George on Monday.

Thanks to everyone for your help!

Sam