Where to begin?

[Reeltarded]

The vid audio sounds like nothing I am familiar with, but it 'feels' like raw voltage dump without restraint.. maybe where that switch was placed. I need more coffee in my mapping function. The images confuse me more than help for now. heh

This might wind up being a case study of what can blocking distortion do at a nearly infinite extreme.. coffee.. be back.

[Reeltarded]

Hey, waiting for water to boil.. let's try something simple.

The swtich that does something with the channels.. lets remove one channel by desoldering that tail wire at bothe ends and removing it. The other channel (just pick one, whichever will not matter) desolder that and the tail of the switch.

At the place where the switch terminates to the PI input (guessing.. not looking at pics) terminate that single channel there instead. It needs a mixer. Use a pair of 270/270k or 470/470k. The signal passes through one resistor and the other resistor goes to ground.

If this works as a single channel amp we have found at least 90% of the trouble.

If that doesn't make sense look up how a pair of inputs mix on a 4 input Marshall or wait until someone clarifies.

I hear water boiling.. coffee!

[horseblanket]

I think I am in over my head with this one.

[didit]

Look carefully. Take your time. Print the schematic and draw the changes. Trace the circuit as it is. GNFB may have been mis-wired or something foolish got into the wiring of MV; that is, beyond putting on a MV. Consider restoring appropriate power filtering.

Best .. Ian

[Reeltarded]

I think I am in over my head with this one.

We disagree! Compare the power amp section from the sockets back to the phase inverter to whatever the schematic is that it is supposed to be. If that all checks out:

1. The switch between channels. Remove the wires that feed it and the one that connects it to the PI.

2. Pick either channel for now. Completely remove the wire that fed the switch from the other channel.

3. The channel you picked will now terminate at a divider we are going to construct from a pair of 1/2 watt resistors. A pair of 270ks or a pair of 470ks.

4. Twist those resistors together at one end. Solder that joint. The channel we are using terminates also to that joint.

5. Terminate one of those resistors where the switch went.

6. The other resistor in that mixer pair terminates to a ground point like the back of a pot.

7. Run amp and see if you get signal without all the raygun noise.

8. DO NOT LICK ANYTHING INSIDE THE AMP BECAUSE IT'S HOT ENOUGH IN THERE TO TASTE LIKE AT LEAST VANILLA

(long story)

I have no way of drawing here but I can cap an example of a mixer pair to show you that the signal from the channel mees the junction of the resistor pair and one of the resistors is signal and the other is grounded. That splits the signal and gives a strong ground reference for the stage. It's simple enough. This at least informs us what is up without you needing to learn a bunch of stuff to discover that switch arrangment is THE problem.

Look at where the switch is in the circuit. Is there a a pair of resistors on either side of it before it dumps into the phase inverter?

[horseblanket]

Vanilla!!!

[Reeltarded]

Vanilla is ok but if you taste bacon probably need to use at least 500v caps.

SIDE NOTE: to be clear with terminology everywhere that I have said MIXER is actually a VOLTAGE DIVIDER. The same parts in a different configuration are a mixer.

[martin manning]

Look carefully. Take your time. Print the schematic and draw the changes. Trace the circuit as it is.

This. There’s no rush.