Deluxe Reverb but my Reverb isn't working!

[ChrisM]

Finally finishing my Deluxe Reverb, sounding great! But o wait its a Deluxe Reverb but with no reverb

The footswitch works fine, tested it. My RCA cables leading to the tank are fine, also tested.

Tried swapping V3 the 12AT7 reverb driver with another tube. All I had was a 12AY7 so I tried that. That didn't change anything. Hitting the reverb footswitch still did nothing. Would a 12AX7 have been a better tube to try?

I looked for damage in the tank. Didn't see anything broken or loose. Got 1.3 ohm of resistance on the input coil (transducer?) of the tank. Got no reading of resistance on the output. That makes me thing there is something wrong with the tank.

Next I measured voltages on V3 the driver tube and the voltages were spot on to verified working builds!

Ok so I tried hooking up a 8R 0.5W speaker to the Reverb Input of the amp. The speaker should work like a mini amp and isolate the problem. No sound from the speaker though!

Right now I am a bit lost. I am thinking its a bad tank. I am also starting to think maybe I have a bad reverb transformer. Either way both are expensive and I would rather get some other advice and opinions before I go spending money on stuff I may or may not need.


Thanks...

[M Fowler]

Reverse the RCA cables and see if that works.

Do you have another reverb amp? If you do try your reverb pan with that amp using the RCA cables to test your new reverb pan itself.

Mark

[Bob-I]

What you can do is test the reverb send, and reverb returns

test connect a speaker to the reverb out jack. The circuit that drives the reverb so when this speaker is connected you should hear output.

Next unplg the return wire from the tank, leaving it connected to the amp. Touch the end of the jack with your fingers. You should hear hum when the reverb is turned up.

One of these tests doesn't work, you can troubleshoot that section for a bad tube or component. If they BOTH workm your tank is bad.

I hope that helps.

[ChrisM]

Reverse the RCA cables and see if that works.

Do you have another reverb amp? If you do try your reverb pan with that amp using the RCA cables to test your new reverb pan itself.

Mark

Mark this is my first amp with tube spring reverb so no extra tank unfortunately. Might ask around at school to see if anyone has an extra tank.

What you can do is test the reverb send, and reverb returns

test connect a speaker to the reverb out jack. The circuit that drives the reverb so when this speaker is connected you should hear output.

Next unplg the return wire from the tank, leaving it connected to the amp. Touch the end of the jack with your fingers. You should hear hum when the reverb is turned up.

One of these tests doesn't work, you can troubleshoot that section for a bad tube or component. If they BOTH workm your tank is bad.

I hope that helps.

Aren't both those tests using the reverb output jack? Thanks!

[ampdoc1]

If the output shows infinite resistance, either you have a broken wire on the output transducer, or internally it is shot. A broken wire in the can be easily fixed, otherwise you'll have to buy a new tank.

ampdoc1

[ChrisM]

^Ya that's what I was thinking.

Touching the "hot" of the Reverb Output I got a nice Buzz! So I guess the recovery stage is fine.

I tried hooking up a speaker to both the Reverb Output and Input. Neither produced sound from the speaker. I forget now I think it was the when I hooked the speaker up to the Reverb Output. Well it acted like a mic kinda, like if I tapped on it or blew on it it would pick the noise up and amplify it. I guess this confirms that the recovery stage is fine.

[rfgordon]

Check the plate voltage on the verb driver tube. You should have a fairly high voltage there-- between 250 and 350 vdc. If that voltage is way low, but it jumps back up when you pull the tube, you may have shorted windings in the verb tranny. I had a short like that in one build that only showed up in the presence of high voltage/current--a straight check with the Ohm meter didn't show the short.

[ChrisM]

Check the plate voltage on the verb driver tube. You should have a fairly high voltage there-- between 250 and 350 vdc. If that voltage is way low, but it jumps back up when you pull the tube, you may have shorted windings in the verb tranny. I had a short like that in one build that only showed up in the presence of high voltage/current--a straight check with the Ohm meter didn't show the short.

With the tube in the plate voltages are both 410V.

[ChrisM]

SOLVED!

Found the tiniest break on one of those wires on the output transducer. It was an issue with the tank. I was able to solder it back on. Geez those wires are tiny though.

Anyways man o man is this reverb great. I am in love with this amp.


Thanks for all the tips and advice!