02-06-2018, 07:07 PM
(02-06-2018, 07:33 AM)jjmt Wrote: IIRC, a properly functioning reverb should lean more towards "overwhelming" than "weak". So, if it's not doing it for you, then it probably deserves some attention. Since it just came back from the shop, is it fair to assume that the tech took the time to check all the resistor values? If he was just doing a cap job, I suppose it's possible that there are components that have drifted in the reverb part of the circuit.
But where I would start is evaluating the tubes. The reverb driver and recovery are the two triodes of V3, and the signal is blended with the dry signal in V2. A weak or imbalanced tube in either spot could result in what you are describing. I would just try different tubes. But if you are like most people and don't have a bunch of 6SN7s laying around, you might just try swapping the two 6SN7s and seeing what the result is? It might give some insight.
I don't know how likely it is that the issue could be the tank. It's not that hard to remove, and I suppose there could be some dust bunnies or something in there that would mute the reverb. Easy enough check. (Well, in my R12R the tank is on the floor of the cab. But if yours is on the side, then that's a bit more work as I would assume you would need to pull the chassis....)
Thanks, I'll try switching the tubes and go from there; I do have a spare set of 6SN7 tubes. BTW, we replaced the 6SN7 preamp tube with a 6SL7. The result was more volume, but I didn't like the tone as much, so back in went the 6SN7.