who is the amp guru

[jimmys69]

As I stated, the reverb tank is hard wired, no rca plugs. The signal to the input of the tank, as far as I can tell, does not go through a transformer, but through a resistor cap network to get there. On the other side of the tank I have either no signal or a very weak one.

You do know that dogman is free right? Well, mostly.

[dragonworks]

You do know that dogman is free right? Well, mostly.

I beg to differ.
Can I unsolder the in and out on the reverb tank then run it through my Super Reverbs tank? The reverb tank is enclosed, it cannot be opened I don't believe. It is about six inches long and three to four inches wide and only about maybe and inch and quater to an inch and a half high. There should be a picture attached. The reverb tank is the large metal box on the right with the old orange paper around it.
free dogman

[jimmys69]

Alrighty then.....

[Steenamaroo]

I'm a relative noob here, but surely you can bypass it for testing, right? Or remove it from the circuit and test it on its own?

[jimmys69]

I'm a relative noob here, but surely you can bypass it for testing, right? Or remove it from the circuit and test it on its own?

Ha! I can finally rep you now!

But waiting til you say something really cool.

[ranjam]

That is the weirdest reverb tank I have ever seen. If you can trace it, knowing which are the input leads and which are output leads would be a huge help. I would ask around and find the oldest tube service guy in your town. Maybe he knew these. Who sold Teisco in your town back in the day? Someone knows this unit. But for me, I'd spend a lot of time messing with the wiring trying to figure input/output.
A rough idea of how to do an RC coupled reverb is here; Channel Road Amplification: Transformerless Reverb Driver
I guess look for the signal at the plate, to the coupling capacitor, and into the pan. From the pan, follow a lead and try and connect a signal to wherever the pan leads you to. Sometimes I'll even just touch the lead with a finger as I turn the reverb volume control. You then know the recovery circuit works. But you have to be sure there is no B+ here!

[dragonworks]

It has input and output labeled right on it. I think I am going to clip the leads and remove it and test it and see if can come apart. There isn't a tube guy within 50 miles of here that isn't backed up for six months.

[Steenamaroo]

But waiting til you say something really cool.

Everything I say is really cool.
Where have you been?

Plus Arcadeko maxed me out.
I've decided max rep is the point where you cease to be polite.

[Steenamaroo]

Hey man,
I'm only asking incase this helps others who might diagnose.

You say it's a stereo preamp and you have reverb on one channel, but not the other.

Then you say you see a strong signal at the reverb tank input, but not at the output.
Are you talking about the defective channel only, or in general?

Maybe this is a stupid question, but is the reverb tank going to have two separate paths for true stereo operation, or is it a summed kind of thing?

The reason I ask is this.
Presumably it has to be a stereo effect otherwise your l+r outputs would be summed.
If it is, you could swap over the channel 1+2 outputs to see what changes. If the fault switches channel there's a problem with the tank.
If nothing, swap back then swap the channel 1+2 inputs. If the fault now switches channel, it exists before the tank.

That way you could rule out the tank without removing or opening it.


Beyond that, because it's stereo and one channel works, you should be able to trace the l+r paths point by point until you find a discrepancy. Maybe a dud cap or whatever.
Perhaps you've been through this.

Apologies if I'm talking crap here.

EDIT: oh, and if you haven't already, confirm that all pots and switches are working. Give them all a good clean to be sure.
If I had a £1 for every time a switch went failed........

[dragonworks]

it is stereo. It has a separate output for each channel. You have a switch for stereo or mono which works. There is only verb and trem on channel two. I have checked the pots with a meter and they are working. I am going to take the reverb tank out, I think it is bad , and test it. I was going to buy a small reverb tank anyways for future testing. Included is a picture of the front of the amp and it can be seen by the decal line above the controls for channel one, from input one to the bright switch for input one, that channel one does not include the rev. and trem. Above channel two you can see a line connecting the input all the way across showing that channel two has rev and trem. I have also confirmed this through testing and tracing the wiring. The quarter I stuck on top is for size reference.
Free dogman