Requesting guidance for troubleshooting reverb.

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professormudd
Posts: 405
Joined: Thu Jul 16, 2020 6:53 pm
Location: Southern California

Requesting guidance for troubleshooting reverb.

Post by professormudd »

Greetings,

I am working out the gremlins in my build. Every noise, hiss, and hum seems to have been dealt with. Hooray! So I finally got around to hooking up the reverb tank. Nothing. No sonic change whatsoever when turning the reverb pot. The springs don't seem to be doing anything either. I am not sure how to approach this. I have checked my connections compared to the layout and verified continuity.

There was one lead from the reverb transformer that I took my best guess at hooking up, as some of the layout had been washed away. The red lead from the reverb transformer I connected to the north end of that 22k resistor on the filter board.

I have a multimeter and eyeballs to diagnose this, but I do not know what to look for. I appreciate any guidance you might be willing to offer.

Thank you.
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Last edited by professormudd on Sat Oct 31, 2020 4:31 pm, edited 2 times in total.
-Matt

It may very well be that the sole purpose of your life is only to serve as a warning to others.
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martin manning
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Location: 39°06' N 84°30' W

Re: Requesting guidance for troubleshooting reverb.

Post by martin manning »

I think your connection for the red reverb transformer lead is correct. What are the voltages on the reverb tube pins?
professormudd
Posts: 405
Joined: Thu Jul 16, 2020 6:53 pm
Location: Southern California

Re: Requesting guidance for troubleshooting reverb.

Post by professormudd »

martin manning wrote: Sat Oct 31, 2020 3:50 pm I think your connection for the red reverb transformer lead is correct. What are the voltages on the reverb tube pins?
These are dc voltages to ground on the third 12ax7, which the reverb connects to:
Pin 1: 248v
Pin 2: 0.1mv
Pin 3: 2.5v
Pin 4/5: 0.1mv
Pin 6: 355v
Pin 7: 4.2mv
Pin 8 2.5v
Pin 9: -0.2mv

Also, when the tank is rattled, I do hear it through the cab.
-Matt

It may very well be that the sole purpose of your life is only to serve as a warning to others.
professormudd
Posts: 405
Joined: Thu Jul 16, 2020 6:53 pm
Location: Southern California

Re: Requesting guidance for troubleshooting reverb.

Post by professormudd »

professormudd wrote: Sat Oct 31, 2020 4:08 pm
martin manning wrote: Sat Oct 31, 2020 3:50 pm I think your connection for the red reverb transformer lead is correct. What are the voltages on the reverb tube pins?
These are dc voltages to ground on the third 12ax7, which the reverb connects to:
Pin 1: 248v
Pin 2: 0.1mv
Pin 3: 2.5v
Pin 4/5: 0.1mv
Pin 6: 355v
Pin 7: 4.2mv
Pin 8 2.5v
Pin 9: -0.2mv

Also, when the tank is rattled, I do hear it through the cab.
I'm ashamed. I had the tank connected backwards. I connected red to red, but apparently it was not correct.

I apologize for the waste of time. Reminds me of the scene from sling blade where they take the mower to the shop because it won't start. Carl says, "ain't no gas in it." "See? thinks of the simplest things first."
-Matt

It may very well be that the sole purpose of your life is only to serve as a warning to others.
thetragichero
Posts: 478
Joined: Tue Sep 10, 2019 7:46 pm

Re: Requesting guidance for troubleshooting reverb.

Post by thetragichero »

can't tell you how many times I've fired up a build and the @$$@& thing won't work only to find.... the guitar volume is on 0 or not plugged in or i plugged into the footswitch or forgot to plug in the cab.... no shame in finding a simple solution!
PRR wrote: Plotting loadlines is only for the truly desperate, or terminally bored.
mirage_indigo
Posts: 84
Joined: Thu Oct 02, 2014 3:34 pm
Location: Longmont, CO

Re: Requesting guidance for troubleshooting reverb.

Post by mirage_indigo »

It's not just you; I just did this on my last build too.

The main thing is that you still have all your fingers and didn't hit the HV rail. That's a win.
We build because we must.
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