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I just bought a used Peavey Classic 50 410 combo and low and behold, the reverb doesn't work on it. Otherwise, this amp sounds phenomenal. The reverb tank seems ok, I get clear reverb when I tap on the springs with the reverb pot turned up, and the volume level of the reverb spring tapping corresponds with the level of the Reverb control setting, in other words, the higher the setting of the Reverb knob, the louder the tapping-induced reverb springs sound - there is just no reverb when an actual guitar is played through the amp. This tells me that the pot is ok, yes? No static, fuzz, nothing, just dry, un-colored guitar tone, as if the control is turned all the way down all the time, until the tank or the springs are physically struck. Any suggestions? I printed off the schematic, but haven't used my schematic experience since College, so any help/suggestions are greatly appreciated.
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The reverb circuit is two parts. The drive section and the recovery section. You have found the recovery part to be working by bouncing the springs and making noise. But that doesn;t test the drive end.
REmove the reverb pan and look inside it. At each end of the spring assembly is a transducer with a small green and black wire running to the nearby jack on the pan wall. The jacks are identified as INPUT and OUTPUT. You already know the OUTPUT end works. Look at the INPUT end then. Are the black and green wires intact? A broken off wire will kill the drive, but may be repairable.
If the wires are intact, then measure resistance across the INPUT jack. You should get a low resistance reading. If you get an open reading, then the reverb pan is bad and needs replacement.
If the pan tests OK, then what is left is the cables back to the amp chassis, and the circuits in the amp. If it gets this far, the problem is most likely the reverb IC in the amp. it is just a 4558, inexpensive op amp IC. While possible, I rarely see the Peavey cables bad.Education is what you're left with after you have forgotten what you have learned. -
Ta-Dah!
Yep, that got it.... Wiring continuity and transducer resistance was all good, grabbed a 6 pack of those op amps at the electonics place for $5, popped one in and caught some tasty waves surfing with the Bigsby on the hollow body....reverb is nice and wet now!
Note to self : Don't get "wise" and assume that the problem is the existing op amp (already a replacement chip) might be plugged into the IC socket backwards and try and 'switch it' around......capacitor smoke is toxic!
Thankfully, I shut it down quick before the capacitor popped, and haven't noticed anything else not working properly as a result.
Thanks for the help, Enzo!Comment
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