Princeton Recording Amp

Released onto an unsuspecting public in 2007 I believe and discontinued sometime in 2010. A short-lived affair that never quite caught on, which in some ways is a shame and in some ways is a relief to be honest.

It’s basically modern, Frankenstein version of an old classic amp with some modern features added, which explains why it looks a bit odd – like an old amp with an extra, modern control panel added. Not that pretty, but it grows on you.

The extra features are: Overdrive, compressor and a power attenuator, which is a proprietary design by Fender. I enquired with Fender in the UK about how it worked when my amp went in for repair (quite common with these amps it seems) and my hunch as to how this thing works was pretty much correct.

The TIPA: Trans Impedance Power Attenuator works, in very simplified terms like this: (by the way I jokingly refer to it as the PITA!)

It sends the signal from the tube power amp into some kind of solid-state power amplifier, the level of which is then controlled by what Fender call the data wheel (not very rock and roll), a stepped control knob, which goes from Silent (speaker off) to Full Volume (attenuator out of circuit) in 15 clicks of the dial. The stomp-box type effects are true bypass when switched off and switchable via the included foot switch as is the FX loop and spring reverb. The reverb sounds sweet enough, but it pretty overpowering above about 2 on the dial.

The Princeton Recording Amp was designed to capture all the vibe and tone of a classic Princeton Reverb (although it lacks the tremolo/vibrato circuit) and it is pretty true sounding to the original Princeton Reverb; pretty much the same cabinet dimensions, except deeper and significantly heavier due to all the extra stuff it has crammed inside it.

I relate it to a hot-hatch car, like a VW golf. The standard car is fairly compact and modest with the GTI version being the same, but with about twice as much engine under the hood and fatter tyres etc.

It’s a loud amp, for 15 watts and the sound of the amp is still impressive at fairly low settings on the power attenuator.

The one big, bad thing about this amp is that if you take it to amp tech for a service, you may receive quite a blunt response like “Sorry I service amplifiers, not computers!”. If you look inside the chassis, it looks like a PC! It may be a tube amp with a 50-year heritage, but it’s definitely a 21st Century design! Maybe this is why it has been discontinued.

If you can find one for a good price on Ebay, you may be onto a good thing. One word of warning though: Many people report of a fault where the amp cuts out in the middle of some overzealous playing at higher gain levels. I can vouch for this as I had this fault myself. It was repaired under warranty, but it still lingers in the back of my mind. I haven’t used my amp live yet, so it hasn’t been enough of a worry to think too much about it though.

Just be warned and make sure you can return your amp to the seller if you experience the fault yourself. Just to clarify though, it sounds excellent, especially with a Tonetubby in it.

After using this amp live for about 2 years I found the Princeton Recording Amp to be a little strained with the duties of regular live use. I went through power tubes pretty quickly as the amp was pushed to the edge all the time and it weighs a ton. I have since been converted to a solid state amp – The Quilter Tone Block, which weighs 4 lbs and has infinitely more headroom. The PRA is in need of a service (it hums and I think needs new capacitors in the power supply). Once I find someone to fix it I will sell it and never look back. The Quilter is the real deal and now all I think I will ever need.

25 Replies to “Princeton Recording Amp”

  1. Mine came with the “fault”. I thought it is a fault too, first. Since I discovered that the volume cut out is not evident up to volume level 6, I see it a little different and think it is just too much sensibility of the built in protection circuit. At this volume level the amp can be run overdriven without volume cut outs delivering full sound that is not really missing higher volume settings.

    Since the amp can be repaired, it seems to be possible to alter the circuit in the way to decrease the sensibility without the amp taking any harm driven hotter than volume 6.

    1. Interesting point Dirk,

      My first impression when it happened to me was that it was some kind of circuit overload protection, but Fender never mentioned anything like that to me. They told me it was a known fault and they replaced the part (the data wheel).

      If your theory is correct and it does seem to make sense, maybe that’s the reason for it. Shame though because for me, the whole point of having an attenuator is to have the amp cranked up full to hear those power tubes singing!

      Thanks for the comment.

    2. Let me just say, that I never experienced the problem running the amp pure tube driven, even cranked up full. Maybe I didn’t use it that much cranked up to full volume level 12 for a longer time. On the other hand it is easy to reproduce the volume cut while overdrive and compressor are on. To me it looks like the signal chain is much hotter electronically when the stomp boxes are on. The reason why the overload protection steps in. Obviously, quite sensitive since the repair allows to drive the amp hotter.

      I had been in contact with a guy who reported a repair that wasn’t a repair. He had then given the amp back to the shop. He also reported having read in some forum that one had returned the amp up to 7 times before it was repaired. It doesn’t look like great support from Fender.

      At least I can say the amp is not defect. I enjoy mine very much.

    1. Although I am happy with the sound of my Princeton recording Amp. I absolutely agree with your comment.

      It’s no match for a traditional Fender amp. It sounds good, but looks like a nightmare for an amp tech.

      Thanks for your comment.

  2. I bought my amp used. It worked beautifully. I used it at a few gigs. Then one day at home when I used my my own stomp boxes with the attenuator turn almost all the way up so I could play at low volume so as not to disturb the neighbors I heard a sizzle and smoke came up through the circuit board that can be seen through the top grill. It sounded and smelled like an expensive fix to me. I called the local authorized
    Fender dealer. He had never fixed one before and asked if I could get him a copy of the circuit layout. Doesn’t exactly instill confidence does it? As of now I am without an amp. Stupid me I had just barely sold my reliable Line 6 amp.

  3. I’ve owned 2 of these amps…..sold one a while ago and missed it for practicing and recording, so I bought another one used, nice, for 7 bills. Works great……BUT, to you true gurus out there who may read this, I want to get RID of that annoying electronic “squeak” every time you power it off……..JEEPERS that’s annoying……..Is there any circuit mod or addition I could employ to stop this? Both of them have done the same thing……I don’t think it’s anything but a factory mishap of engineering. What say ye?

    1. Hi Tom,
      I think this is a design fault as mine does the same thing and everyone I read about who has this amp says the same thing. I get the loud squeak when I power on.

      This amp does sound really good, especially with this Tonetubby in it, but I think Fender dropped the ball a bit with this model. Not on sound, but on stability. It’s really heavy for a small amp too!

    2. I have had PR’s, DR’s, Pro-R’s, and Vibro-R’s… well as my Bandmaster-R…..and I LOVE this amp, especially for practicing and recording, but there MUST be a way to solve the problem……..

      I wish Fromel or Moyer or SOMEONE would take this head on……It’s pretty clear Fender isn’t going to at this point, although they certainly SHOULD for the price these things go for…………Good grief………Like the new “Custom Vibrolux Reverb”… is the noisiest amp they’ve EVER made, and no fix from Fender offered… took simple ingenuity from independent techs to solve it……and they DID solve it….. I’ve modded them with fabulous results. I just want the power squeak GONE.

    3. I love this amp also, but after having the sizzle and smoke experience when I chained my effects pedals while using the attenuator I am wary of using the attenuator. Fortunately, the overload only took out a resistor on the power supply circuit board (Apparently, a tube was putting out more voltage than normal for some reasonl). I was happy that it wasn’t the data-wheel which seems to be a common problem My brother who is an electrical engineer easily took care of the problem. I should have asked him about the squawk and squeal which I sometimes get and seems to be common with my many owners out there.
      While inquiring to Fender about the warranty I talked with a tech and asked him if there was a permanent fix for the attenuator problem and he said he had never heard of one, which is hard for me to believe. I guess that would be admitting there was an inherent flaw in the design, eh? Although, everyone knows there is.

    4. Yeah, the attenuator…… On my first one (I bought used), the attenuator was loose….you could push it in and out, and it would or wouldn’t work depending on the position you put it in….I tracked it down directly at Fender in California, and swapped it out…..after that, it worked great….but still had the squeak. I had to swap out the reverb tank too, as it was VERY noisy (electrical hum)……after the new one, it was quiet as a mouse. So IF you have one and the reverb circuit is pretty noisy, you might want to swap the tank with a new Accutronics or MOD…..Could be a cheap and easy fix.

    5. Hey Gary,
      It seems like I just experienced the same thing as you with the sizzle and smoke! On inspection I think, but can’t be sure that I may have located the resistor in question that may have burnt out. It doesn’t look too bad, but it looks a bit discolored. I turned the amp off within a second or two of hearing the sizzle then seeing the smoke start.

      Can you remember or do you know at all if that resistor was the one right next to the power tube closest to the power socket (the fursthest one to the left as you look at the back of the amp?

      On the circuir board it is labelled R40 and just the other end of it there is a label for another connector called P23.

      If that is the resistor, do you know the value of it. I’m going to try and fix it myself, seeing as it is well out of warranty and here in Phuket, Thailand I will be lucky to find an amp tech to work on this.

      I hope you have some info that will help me. Thanks.

  4. After my brother fixed it and I turned it on for the first time there was quite a bit of noise coming from the Reverb Tank, but after a few seconds it quieted down to nothing and haven’t had a problem since.
    Anyone try different brands of tubes in amp?

    1. Hi Gary,
      Another question regarding the “up in smoke” problem.

      Did it transpire that the fault (which you explained was due to too high a voltage from one of the power tubes) that the tube in question needed replacing. Perhaps the tube malfunctioned, causing a knock-on effect.

      I might replace the tubes as a safeguard in case it happens again immediately after fixing it (assuming I can fix it).

    2. Rob,
      do you have the schematic? If you need it I can send it to you. You should be able to find the Rvalues from that. Just email me at m2dad at yahoo . My brother seems to remember it was either resistor R42 or R43. I seem to be remember that there was a power surge to one of the tubes. Since the resistor was replace I have no issues with the amp. I use it just about daily. However, I do not use the attenuator for fear the issue might occur again.

    3. Hi Gary,
      I got my amp fixed. It was indeed R40 that had burnt out, but also another resister took a hit in the power supply section – R43 I believe. It was caused by one of the power tubes dying (it had a good innings, being cranked for 5 years).

      I was lucky to meet, quite by chance a local guy here in Phuket who can fix anything electronic and he did it for me. Great to know there is somebody local who can take care of stuff like that.

      It’s now singing like a bird again with new tubes and sounds great.

    4. Glad you got it fixed and found out the cause of the problem.
      I have a feeling that my amp will sound better if I replace the 6V6’s. It doesn’t seem to have the clean sound it did when I first got it so I suspect that when the resistor fried on the power supply board it damaged a tube, or the failing tube led to the resistor sizzle. Fortunately, my brother will be able to bias the matched pair when I get them.

  5. I have the cut out problem also. Changed all tubes but it still cuts out. I am going to try thermography of the PCB to identify the component at fault.

    1. That sounds very interesting. I’ve not experienced the problem for a while, but I’ve been driving the amp far less than I used to for cleaner sounds. I would be very grateful if you could report back on whatever your findings are and any solutions you may find also. Thanks for your input.

  6. Never got around to the thermography of the PC board. I have been playing the amp upside down and have not had the cut out problem. I think the heat from the tubes is the real problem. May we need a cooling fan?

    1. Hi Brendan
      I believe that to identify the tubes you count from the farthest tube away from the large power tubes (so the opposite end of the big tubes).
      According to the tube chart printed in the side of the amp, the second tube (so V2) is a 12AT7.
      Hope this helps.

  7. Hi,
    I own a PRa since 10 years , and it’s work well until now .

    it cut after 30/45 min maybe because too much heat ?
    i do not use all electronic stuff in it ( attenuator , overdrive ..)
    Maybe if we can mod it to bypass/disalbe attenuator it will be cooler in it ?
    Anyone know how to do that ?
    Julien from france ..
    sorry for my poor english ..

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