Hi folks,
this is my first post so hi everybody.
I recently finished my second amp with reverb but the reverb doesn't work as it's supposed to.
It's a standard reverb circuit like in every other Fender amp (actually it's the Vibroverb 6G16 circuit).
At time I'm trying to locate the problem and want to post what I've already done to locate it.
If my assumptions are wrong I would appreciate any answer to get me right.
When I turn up the reverb pot I can hear slightly more hum increasing in the speakers.
I can hear the reverb (springs) in the speakers when I nudge the reverb pan. That should indicate the recovery circuit as working.
To make sure it's got nothing to do with the reverb tank or cables, I hooked the unit to another amp and it worked fine. The other amps unit did not work on the new amp.
I swapped the tubes (they are brandnew) with two different ones known to be ok. Still no change.
Then I got back into the circuit. I measured the voltages of the reverb transformer. Red wire reads 300V blue wire reads 296V. Seems OK for me. Haven't measured the cathodes voltages yet. When I touched the annodes of Tube1 (driver tube) with the tip of the multimeter I could hear a krackle in the speakers mixed with reverb. That should indicate the driver circuit and the transformer as working too.
So far I have a working reverb unit(?), only the guitar signal doesn't go through. I suspect the 500pF in front of the grid of Tube1 to be broken but haven't changed it yet. (see attached schematic)
Any other suggestions?
Thanks
Matt
this is my first post so hi everybody.
I recently finished my second amp with reverb but the reverb doesn't work as it's supposed to.
It's a standard reverb circuit like in every other Fender amp (actually it's the Vibroverb 6G16 circuit).
At time I'm trying to locate the problem and want to post what I've already done to locate it.
If my assumptions are wrong I would appreciate any answer to get me right.
When I turn up the reverb pot I can hear slightly more hum increasing in the speakers.
I can hear the reverb (springs) in the speakers when I nudge the reverb pan. That should indicate the recovery circuit as working.
To make sure it's got nothing to do with the reverb tank or cables, I hooked the unit to another amp and it worked fine. The other amps unit did not work on the new amp.
I swapped the tubes (they are brandnew) with two different ones known to be ok. Still no change.
Then I got back into the circuit. I measured the voltages of the reverb transformer. Red wire reads 300V blue wire reads 296V. Seems OK for me. Haven't measured the cathodes voltages yet. When I touched the annodes of Tube1 (driver tube) with the tip of the multimeter I could hear a krackle in the speakers mixed with reverb. That should indicate the driver circuit and the transformer as working too.
So far I have a working reverb unit(?), only the guitar signal doesn't go through. I suspect the 500pF in front of the grid of Tube1 to be broken but haven't changed it yet. (see attached schematic)
Any other suggestions?
Thanks
Matt
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