Then I went to v9 and got lots of noise. I then went to v10 and again, got lots of noise. So it's both of those sockets, which explains why my previous test of pulling just the inside and just the outside tube pairs didn't get me anywhere.
Ok, überfuzz seemed pretty sure of his bad solder joint diagnosis, and in the end that's what it was, so I guess he gets to gloat a little bit. I had re-flowed the solder joints to the resistors I was worried about and still had the problem. I pulled the PI tube again and started poking and tapping everything around the power tubes and the circuitry leading up to them and was not getting anything, then my brain finally turned on and I started tapping the wires to the PI tube socket and bingo, lots of noises. I re-flowed the solder joints on each of the PI socket pins and the popping and crackling is now gone.
Thanks to everyone who chimed in. I got lots of good suggestions and they ultimately got me to the right place.
Any ideas on how to fix a solid state bass amp (EBS session30) with the exact same noise?
As far as I can see, all soldering work in ok. The only weird stuuf in my opinion, is a little white powder scattered over the PCB, but seems harmeless. Cleaned with a brush.
The noise acts with no instrument plugged and i the phones out too.
Please let me suggest you start a new thread for your amp in the repair section. This thread has been dead for over two years and was about an old Fender tube amp, not a solid state amp. You will get a better response that way.
Education is what you're left with after you have forgotten what you have learned.
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