Members KjStrat62 Posted September 26, 2015 Members Share Posted September 26, 2015 Fender twin reverb 65 reverb problem here. When i got amp reverb worked fine. I Installed tilt back legs on the amp. Ever since reverb has stopped working. Checked the tank all tubes rca jacks. Even tried a different reverb tank. Nothing. Then put that tank back in the other amp and reverb.Existing tank i see no broken wires. Im stumped. What to look for next? Loose wire in chassy.?? KJ Link to comment Share on other sites More sharing options...
Members onelife Posted September 28, 2015 Members Share Posted September 28, 2015 If you bump the amp do you hear the amplified sound of the Reverb springs crashing together? (Note: Be sure to perform this test with the Reverb control turned down quite low) Link to comment Share on other sites More sharing options...
Members onelife Posted September 28, 2015 Members Share Posted September 28, 2015 Are you certain that you connected the Input and Output RCA plugs to the tank properly? Link to comment Share on other sites More sharing options...
Phil O'Keefe Posted September 28, 2015 Share Posted September 28, 2015 Fender twin reverb 65 reverb problem here. When i got amp reverb worked fine. I Installed tilt back legs on the amp. Ever since reverb has stopped working. Checked the tank all tubes rca jacks. Even tried a different reverb tank. Nothing. Then put that tank back in the other amp and reverb.Existing tank i see no broken wires. Im stumped. What to look for next? Loose wire in chassy.?? KJ If the tank is known to work (because you put it into another amp), then the issue is with the cables, or the driver / recovery circuit in the Twin... or, if the tank is in a tolex bag, sometimes the bag gets bunched up and comes into contact with the springs and prevents them from vibrating freely. I'd check that first... then check the cables with a DMM set to check continuity (or just swap them for "known good" cables), and as onelife mentioned, make sure you have them connected properly and not reversed. If neither of those solve your problem, the next step is to try replacing the reverb preamp tube. Link to comment Share on other sites More sharing options...
Members KjStrat62 Posted October 4, 2015 Author Members Share Posted October 4, 2015 Great advise guys but Im baffeled. Had amp checked out by local amp guy. He said Reverb tank bad. OK.. So i get a Mod 17 inch replacement tank. Plug it in .. NOTHING..You can tap on tank and hear a splash. Amp guy checked everything. Input output connections. Pre tube. RCA chords etc. What gives next? KJ Link to comment Share on other sites More sharing options...
Members onelife Posted October 5, 2015 Members Share Posted October 5, 2015 The Reverb send on a Fender amplifier produces enough current to drive a small speaker. Try hooking up a speaker to see if the Reverb driver circuit is the problem. The Reverb return on a Fender amplifier is sensitive enough to plug a guitar in to test if the return circuit is working properly. Do the re-issue Twins have RCA jacks for the Reverb or are the connections hard wired to the amp? Link to comment Share on other sites More sharing options...
Members KjStrat62 Posted October 5, 2015 Author Members Share Posted October 5, 2015 rca Link to comment Share on other sites More sharing options...
Members onelife Posted October 5, 2015 Members Share Posted October 5, 2015 If there are RCA jacks on the amp then it should be easy to connect a speaker to the Reverb send and connect a guitar to the Reverb return. If both of these tests work then it will verify that the electronics inside the amp are working. If either the speaker doesn't work or the guitar input cannot be heard then that will point to either the reverb driver circuit or the return (unless there is a problem with the test itself) Link to comment Share on other sites More sharing options...
Members WRGKMC Posted October 5, 2015 Members Share Posted October 5, 2015 What replacement tank exactly? Tank come in all kinds of impedances from around 4 ohms all the way up to thousands.If you didn't know this and bought a tank specifically matched for your tube amp, you may have a tank with an impedance so high it cant be driven by the circuit. Also the 12AT7 tube drives the tank and 1/2 of a 12XA7 tube receives and amplifies the reverb return signal. Either tube could have failed at some point. Rare but it happens. Also the reverb foot switch can be a problem. The pedal just shorts the signal to ground. If the pedal is removed, it should rule out it being the issue. Link to comment Share on other sites More sharing options...
Members onelife Posted October 5, 2015 Members Share Posted October 5, 2015 Also the reverb foot switch can be a problem. The pedal just shorts the signal to ground. If the pedal is removed, it should rule out it being the issue. Good point - that should have been the first test. Link to comment Share on other sites More sharing options...
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