Classic 30 Reverb Help

[B.Daws]

So I bought a Peavey Classic 30 head and the reverb in it doesn't seem to work. I have worked on guitars, effect pedals and amps but never on reverb tanks. Any ideas on what to check and look for first? Also any way to test the tank itself? I also bought an old Delta Blues cab that has a tank in the bottom of it so surely I can get one of the two tanks to work. Thanks for your help and feedback in the matter.

 

A side question, I don't have the footswitch yet but is it possible the last person turned the reverb off with the switch and I need a switch to engage it again?

[Mr.Grumpy]

Reverb tanks are very simple electro-mechanical devices. On some amps, the reverb tank is inside a cloth bag to prevent feedback, on others, it's just bolted to the cabinet. Remove the reverb tank and make sure the springs aren't broken. You can't really replace the individual springs, just replace the whole reverb tank, a new replacement is only about $30 mail order.

 

If the springs are OK, then make sure the little wires to the drive coil and pickup coil are intact. You can check the drive and output coils with an ohm meter. Exactly what the resistance is supposed to be depends on the model of reverb tank, but is should be in the hundreds to thousands of ohms range.

 

Make sure the connections and cables to and from the reverb pan are good. Lastly, many tube amps have a preamp tube dedicated to driving the reverb, but I'm not familiar with the PV classic 30 in that regard.

 

Again, I'm not familiar with Peavys, but on Fenders you don't need the footswitch to activate the reverb - in fact the footswitch "shorts out" the reverb - otherwise the reverb is always ON, (if you don't need, you turn the reverb knob to zero).

[B.Daws]

Thanks for the info Mr. Grumpy!

[FXR]

The reverb is solid state driven. Looks like it's using U1 a 4558 OP Amp and Q1 which I didn't identify. They are controlled by pot VR4.

 

In the board layout the components are on the pot side of the PCB pretty much in the middle right by the reverb pot.

 

Here's the schematic. http://www.blueguitar.org/new/schem/peavey/c30schem.gif

 

Here's the PCB layout. http://www.blueguitar.org/new/schem/peavey/c30layg1.jpg

 

This might help if it's not the tank.

[WRGKMC]

Had to read your post there FXR twice. I first thought you were saying solid state reverb then saw you said Solid State "driven" which is correct. The schematic doesnt say if its a stand alone head or combo though but the circuits should be simular. Be sure to try a footswitch and make sure that isnt all thats needed.

 

You can test the signal going into the tank with an audio tracer and see if the amps putting out a signal to the reverb. You can also unplug the return and see if the center shielded wire hums when touched, like a guitar cord. that will tell you if the problems the circuit or the tank too.

 

For an audio tracer, you can simply use a small battery powerd amp. Connect a small capacitor of say 1uf to the hot lead and use the other end of the cap as a test probe. The ground obviously cts as a ground. The cap will prevent DC loading when tracing the circuit so you can see if any sounds coming out of the amp into the tank.

 

 

The other thing is, if you do need a new tank and its not just a broken wire or bad connector, Be sure to get a tank that has the same impediance. Theres like 50 different types of tanks out there all with different ohms from a few hundred up to tens of thousands of ohms. What might work for a tube driven low impediance reverb circuit wont work for a high impediance solid state driven circuit like you have, so google up what tanks needed for your amp. You can also check the tank itself. You may have it written on the tank or have a part number there you can google.

[B.Daws]

Footswitch didn't do it so I will be tearing into the amp on Sunday. Thanks for all you help guys and I'll get back on Monday to let you know my findings.

[B.Daws]

Thanks for your help guys. I didn't realize the plugs are simple RCA adapters that go into the tank. So I removed the one in the head and swapped the tank in the cab and it now works beautifully. Thanks so much!