Strange that they did it that way–why not just use a lower grid leak? We’ve added some “new” guys to the moderator crew. Of course, staying at home with the flu would be an opportunity for some to spend more time debugging their amps, LOL. Awesome–glad you fixed it! Like a said before, increase the cathode resistor to 2.
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The Amp Garage
Your name or email address: C1 is pretty much redundant, so I’d eliminate jumper it. This will absolutely confirm the recovery side is working and eliminate it from worry.
I’ve done this to dozens of Fender amps I want to thank you guys for the help! Strange reverh they did it that way–why not just use a lower grid leak?
Very simple – replace the 12AT7 reverb tube with a 12AU7. Jan 30, 7. I haven’t had time to get into more troubleshooting this week even though I was home 3 days with the flu.
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It’s hard to say without knowing the AC voltages in the other stages. That input impedance makes all the difference. While you’re at it, record the plate voltages in the amp to make sure everything is functioning properly. The 8F tank should still have worked. Jan 30, 9. I run 12au7s for reverb drivers in my Fenders.
Taming the reverb on a super reverb.
Jan 30, 8. If you need more drive, short out the K. They can and do open up electrically. That means that either the revern tank was damaged in shipping or its input impedance is too high and blocks the signal.
Could that cause a problem? Jan 31, deverb Last edited by Natman; at I ain’t fussy, they sound fine to me and I have at least 40 organ pull 12au7s.
BibsJan 30, I looked at an Ampeg schematic and you’ve got R9 and R8 connected incorrectly. And yet another update: BibsJan 31, Will-Jan 29, If you’re not seeing signal driving the tank, then check the grid of V2A for signal. Yes, drop R9 to improve your reverb signal. Thanks very much, guys! You don’t want the bias current to be any higher than 10mA, increase the cathode resistor if the current is too high.
The rest of the circuit is the same.
Taming the reverb on a super reverb. | The Gear Page
Out of curiosity, did that first tank’s input transducer test okay for continuity with your R-meter? Have a look at revetb diagram if you please.
Most of the Ampeg amps which use this type circuit use a 6CG7 or 6SN7 driver – off the top of my head, those tubes have a bit higher allowable plate dissipation than a 12AU7 type tube but are otherwise very similar. Maybe the tank itself is bad.