diytube.com

i have a PP 2xel84 guitar amp, PCB construction, and when i hit notes hard, or even not so hard, there is a nasty buzz, and a partial volume drop/ complete volume drop, that usually recovers in a second 2. its been doing this for awhile now. if i bang on the amp or wiggle tubes, it seems like it has a very temporary remedy effect...
the problem is intermittant too, but when it is doing it, it is bad. i played with dropping line voltages with a variac, and that doesn't seem to have an effect either.
i have ruled out any and all tubes.
so at this juncture i'm thinking bad solder somewhere, but based on my description, can anyone narrow down which part of the circuit/tube socket may be suspect? i examined the PCB, and lots of it looks like cold/inadequate solder to me. it is a rather complicated circuit(Orange Tiny Terror), and the PCB looks impossible to remove without lots of surgery due to PCB-mounted jacks and pots...schematic was unavailable at last query....
last, but probably most significant fact: this amp never had a problem, until i removed the transformers to paint them due to mounting corrosion on the bells....but i have looked at my resolders and they really seem solid.
cheers

pic of the suspect-looking solder:

Sounds like something is causing enough of a LF "whump" to cause blocking for a couple seconds.

Redo every solder joint is my suggestion. It may look good on the outside, but inadequate heat could mean just a blob of flux on the inside.

Cheers!

yeah i resoldered a bit last night, but i am confused as to how they even wedged this thing together. the radial cap leads are of course inaccessable without surgery. the pcb-mount controls and jacks really suck...i can't even really desolder them, it basically seems like i might have to actually rip the board out and damage stuff...
but, thats how they made it "Tiny"

That's bad business.

Even if it was built right the first time, it makes it impossible to service.

Northern Telecom had no problems making things tiny, yet easy to service

Cheers!

I'd look over the power supply / B+ string, it seems like there is a case of voltage 7 current starvation during heavy usage, , which takes a few seconds to recover. As with most of these intermittent "dog" problems, bad solder connections or corrosion iis the usual culprit.

I'd go ahead and reflow any suspicious looking solder, especially around trhe PSU string and teh EL84 power outpyut section.

HTH

/ed B