Reduced volume with reverb on princeton

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rutledj
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Joined: Sun Sep 17, 2006 2:08 am

Reduced volume with reverb on princeton

Post by rutledj »

Hoping you gurus can help. I did a "retro" build of a princeton reverb. Everything works perfectly unless I try turning the reverb up. When I do, the volume decreases quite a bit (more than half). Reverb does work, just lose a lot of volume.

I have checked and rechecked wiring and components. Replace tubes a couple of times. Does it whether tank is plugged in or not. I've attached pics. Open to any suggestions.
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rutledj
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Re: Reduced volume with reverb on princeton

Post by rutledj »

This one is a real puzzler. Can anyone tell me what kind of signal level I should see coming back from the reverb tank compared to the tank input? Also, shouldn't the signal out of the reverb recovery tube be in phase with the signal out of the 2nd preamp tube (input of 3.3 meg resistor)? Mine appears to be out of phase.

If I disconnect the tank and jumper across the reverb jacks, there is no loss of signal. Really confused on this one.
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xtian
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Re: Reduced volume with reverb on princeton

Post by xtian »

You may have oscillation due to lead dress at the reverb tube driver socket. There was a thread recently on this subject. The plate wire (pins 1 and 6) must loop AROUND the socket:
Screenshot 2025-09-22 at 8.35.39 AM.png
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Stevem
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Re: Reduced volume with reverb on princeton

Post by Stevem »

If you unpower the reverb drive transformer ( lift the red wire does the volume drop still take place?
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sluckey
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Re: Reduced volume with reverb on princeton

Post by sluckey »

Just adding to what xtian said. This may not fix your issue but there is some reason that Fender looped that pin 1 to pin 6 jumper on all their amps, including the PR.
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rutledj
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Re: Reduced volume with reverb on princeton

Post by rutledj »

I'll try the looping trick. Disconnecting the reverb transformer still has the same issue.
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