MOSFET reverb buzz

[mickeydg5]

Is this the same configuration as the old pan?
Do you still have the old pan?

Again, he already gave those details.
He gave the exact model tank, same as the old and the new.

 

[Ebwelds]

Btw. Thank you all so much for your help figuring this out

 

[ampmadscientist]

Btw. Thank you all so much for your help figuring this out

Can you post pictures of the old tank RCA jacks so we can see both jacks on both tanks?

 

[mickeydg5]

Btw. Thank you all so much for your help figuring this out

The deed is not yet done.

 

[Ebwelds]

Can you post pictures of the old tank RCA jacks so we can see both jacks on both tanks?

Here you go. You can see the out is grounded to the chassis and the in is insulated from the chassis the same as the new mod version. also out of curiosity I started probing the capacitance of several of the capacitors. I found that I can’t read the capacitance of any of the pink ones thought they all have resistance and 2 of the 22uf read oL. And one 22uf reads 28 uf. So far. The rest seem fine. If that seems alarming I’ll show yeah which ones on the schematic.

 

[Ebwelds]

As a matter of fact I think it is important looking at the schematic because they are c51 (which goes from the ( foot pedal to reverb on/off transistor) to ground or 0 v) and the other is c59 which

Did you reverse the input output cables to the reverb pan?
Did you ground the reverb pan metal enclosure?
Everything you are describing is a grounding issue at the pan, not a circuit problem.

 

[mickeydg5]

Btw. Thank you all so much for your help figuring this out

What happens when you turn the REVERB to OFF using the footswitch with REVERB turned up a bit?

Read this and reply.

 

[Ebwelds]

Here it is on the print

 

[Ebwelds]

Read this and reply.

when I click the reverb on it hums. When I click the reverb off it does not. I’m 100% sure the hum is in the reverb section on the circuit

 

[mickeydg5]

How are you measuring/testing these capacitors?

 

[mickeydg5]

when I click the reverb on it hums. When I click the reverb off it does not. I’m 100% sure the hum is in the reverb section on the circuit

Yes it is.
Does it still hum with REVERB tank out disconnected?

 

[Ebwelds]

How are you measuring/testing these capacitors?

Yes it is.
Does it still hum with REVERB tank out disconnected?

I’m using my multimeter on the capacitance setting. And no it doesn’t hum with the tank disconnected. And the old tank simply doesn’t work so I can’t compare them.

 

[mickeydg5]

I’m using my multimeter on the capacitance setting. And no it doesn’t hum with the tank disconnected. And the old tank simply doesn’t work so I can’t compare them.

Is the amplifier ON or OFF when you measure capacitance?

Now connnect REVERB tank out and disconnect REVERB input. Hum?

 

[Ebwelds]

Amplifier off when measured.