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Dirty-South Blues Harp forum: wail on! > Princeton Reverb Reissue
Princeton Reverb Reissue
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275 posts
May 18, 2021
7:02 PM
I got a PRRI for a mid-sized gigging amp, mostly based on some recommendations I read here. I thought I'd share my thoughts since I've been playing it for a while now, and ask a question.

First, the mods ...

- Changed one of the pre-amp tubes from 12AX7 to 12AT7. I don't remember which one. I experimented to find the one that sounded best. With the tube swap I get a lot more volume before feedback. I use a Lone Wolf Harp Shield with it and have almost no feedback problems, even at very high volumes.

- Changed some coupling caps to larger values. This made no real difference.

- Changed the speaker to a Weber Alnico 10A125-O. This greatly improved the sound.

- Added fender tilt-back legs. This really helps to increase the apparent volume of the amp on stage, and lets you hear it a lot better.

- Added a power soak in series with the speaker. Its a DIY soak with a switch to change from 100% to 50% power. When set to 50% this is allows me to get a lot more breakup at lower volumes.

My thoughts on the amp ...

My band mates love it. It cuts like a knife through the mix.

Its loud. 15W is a lot more than you think. I play it with my full band, and its always loud enough. Only once have I been in a situation where it wasn't loud enough, and that was a blues jam with ridiculously loud guitars.

Its got a lot of punch and is very responsive to technique. Its also has a lot of crunch, and the breakup sounds great - especially when I have my power soak at 50%. I'm mostly using a Brown Biscuit mic with CM element with it. Everyone seems to like the sound. But to my ears its too bright. I have the treble set to 0, and the bass on 10, and its still too bright for me.

The reverb sounds good, but can be too much. Anything beyond 2 or 3 is overkill.

Overall I'm happy with it. It's punchy, cuts through well, breaks up nicely, and I can crank it loud without feedback. A little bright for me, but overall gets the job done.

Now the question:

My PRRI died at practice this weekend. The power supply dropping resistor to the power tubes burned (1K, 2W). I assume the most likely cause is a power tube failed. I'll replace the resistor and the power tubes and it should be fine. I don't begrudge the occasional repair on a tube amp. This is the price we pay for using old technology. It happens. But this brings me to my question. Is the PRRI known to have reliability issues? Has anyone else had similar issues or heard of similar issues with these? Hopefully I just got the random bad power tube, or maybe they weren't matched well at the factory.
390 posts
May 19, 2021
8:47 AM
Quick reply on brightness.
I like the Lone Wolf Tone+ for that with my original. YMMV.
(My AT is in V2; V1 is a 5751.)

Last Edited by TetonJohn on May 19, 2021 8:49 AM
6953 posts
May 19, 2021
8:14 PM
I have heard the occasional report but nothing to suggest the kind of design weaknesses such as exist in some of the cheaper fenders.
My friend complained about his 68RI amps needing tubes not long after purchase and speculated the amp may be hard on tubes. Eventually concluded the stock tubes were an inferior product as the replacements lasted much longer.

I run a 78 PR. Completely different amp in construction and components but very similar circuit. My reverb was a bit much but I put a lower gain tube in V2 and I like it better. I know I've made several tube substitutions in it but once I became really happy with it I stopped messing about and now I've forgotten the specifics. Pretty sure I changed the phrase inverter tube. And probably v1 as well. Lol.
I have the same model Weber speaker as you and agree it was a good change.
I really like the amp. I probably like it more than my Sonny Jr 2 in some ways. I've said before that if I advertise it for sale you'll know I've given up playing amplified harp. I expect it will form part of my estate.
277 posts
May 23, 2021
9:51 PM
I fixed the amp with new power tubes and replacing the burn power supply resistor. Hopefully it was just a random bad tube,
Jimmy Famous
9 posts
Jun 08, 2021
9:38 AM
I have a 65 Princeton Reverb Reissue (the black one). I love it. I plug in my Bulletini mic and away we go. I also just purchased another one from sweetwater that has the 12" cannabis rex and tweed finish. Even better!
No mods, no pedals, just sweet tone.
I do tilt it back with a 12" long stick of wood.
Maybe I should get the legs from fender??

Last Edited by Jimmy Famous on Jun 08, 2021 9:41 AM

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