Princeton Reverb Amp Kits

I recently built a Tube Amp Doctor kit, which I understand is a re-badged Mojotone one. I used the instructions available as a download from StewMac and it worked great first time. I followed the TAD layout, which I've since found out incorporates the Stokes mod; this increases the signal to the phase invertor from an un-used power node, which increases the headroom so it breaks up a bit later. In conjunction with the 12" speaker and bigger trannies, the PR will give any DR a run for its money.

The StewMac kit is also Mojotone supplied. https://www.stewmac.com/How-To/Onli...its/65_P-Reverb_15W_Amp_Kit_Instructions.html


Good quality cab, good components etc. I swapped all the carbon comp resistors for metal film, and the floor noise is zero. I also added some of the recommended upgrades listed on the Robrob site- https://robrobinette.com/AA1164_Princeton_Reverb.htm

I'm tempted to build another in Brownface trim with a stock circuit and 10" speaker just for fun. If I was to do it again, I'd use a turret board rather than a tag board. It's easier to keep things in place when populating the board, and better for swapping components later on.

I'd also use smaller caps in the trem section. The Orange drops are a royal PITA.

The trem is a little weak, but that could be down to tube bias, but it's good enough. if I ever tear it down I'll do a couple of cap swaps to make the wibble wobble deeper.

I'd say go for it. At least as good as the real thing but without 40 years of wear and tear. The only real difference in the Black and Silver face circuit is as you say, the push/pull on the later version.

 

Here's the thread of the one i built, with a few gut shots.

http://www.gretsch-talk.com/threads/ive-been-turned.192568/

 

Well yes, the sound of the push-pull switch faciliy is rather an agressive and crunch, but this can be modified in a valuable footswitchable booster option, the kind you need to just push your amp into smooth overdrive and compression. It's what I did on mine...

A+!

 

I’ve learned recently:
The Silverfaces and the last Blackfaces until 1981 shared the same circuit except the push-pull volume. It’s an option, but no need to use it

 

I'm sure this apply for Champs, they're always been basically the same amp.
If this is true for Princeton as well, I wonder why one has to spend double money for a Blackface. Over here a Silverface Princeton costs about 1500 euros, a Blackface (or pre '68/69) not less than 2800.
Like I said I'm no expert, but by ears I always found some difference between Black and Silver face Princetons (mainly Silver have a more "icy" tone and a different grain of saturation, more definite than Black which is more growling and has warmer cleans), apart from those transitional years where they were basically the same amp with a different case.

That would be good news thought: I've been offered a '74 Princeton with non-original speaker for a bargain price lately. I passed because I wanted to have a blackface... in this case, I may reconsider it.

 

Silver face have a different rectifier tube, and the bias cap is a little bigger, the power transformer may be wound a little different but CBS left the circuit almost in tact. They sound a little different to the discerning ear but both beat anything on the market today in my opinion. I own a 66. I played a 70’s silver face at GC in Iowa. Chord, Tele. Plugged into every amp in the store. Nothing touched the Princeton for 3D sound, glass, and harmonic richness including a reissue sitting right beside it. They are magical amps. That circuit is much different than the Deluxe that is so popular. I can’t live without one.

 

A funny tale of Princetons: A couple of years ago I went to see Mark Lanegan band to play in Florence (in one of their latest lineup, the one with a lot of electronics into it). The guy at the main guitar (played a Black Les Paul standard with Bigsby mainly) had a great, great sound. Behind him there was one of those new AC30 made in China, head and cabinet. The sound was really huge. At the time I had an AC30 cc2 too that I never bonded with, so I was wondering what pedals or what setup he could have for obtaining a sound like that. Also, I was asking myself why the head+cabinet version sounded so much better compared to the combo...
After the gig (The house soundman was a friend of mine, and he was doing stage monitors) I stepped up on stage to check the guy's rig. I noticed the Vox cab wasn't miked. Well, that was because on the back of the cab were sitting two Blackface Princetons, both miked, placed backwards to the front stage. Nobody could see them because the cabinet was in front of them and completely hide them from the crowd viewpoint. I don't know if it could have been some endorsement issue, but it made me smile.
Sometimes the best kept secrets are the simple ones.

 

The differences are very small, it‘s the same circuit (besides the push-pull option) in an MDF-cab whereas the blackface cab is made of pine. Will you hear that? Dunno, but this may be a 5% difference but a different speaker generates at least a 30-40% difference in tone.
Received mine yesterday, everything cleaned up and installed the Emi Allessandro:

 

Hey Tim, I have a few Princeton's and find them to be among my most useful amps. They get plenty loud for most applications and they sound great. Two of my PRs are blackface clones built by a very talented guy in Toronto named Brian Luckhurst.

In the daytime Brian makes custom radar intallations for ships and at night, builds the sweetest blackface PR clones I've ever heard. Pine cabs, choice of speakers etc.

Pricing is in the $1,000 to $1200 range - CANADIAN. Yes, he ships to the USA.

I have a silverface PR in a 12" cab and an Allen SweetSpot to compare them too. I also had a '68 custom but just sold it as it wasn't being used much. They all sound terrific. I have a Luckhurst clone in 15 watts and another in 22 watts. While the 22 sounds wonderful, I tend to use the little 15 more often. The Eminence Legend 1258 12" is a very sweet match for the PR. Intall it yourself after you recieve the build and save some money on the shipping.

PM me if you want contact details.

 

I'm using a modern Jensen C12Q, with a sensitivity rating of 93, which is great for round the house. Very, er, Fendery and not overly loud.

 

They are great amps. Stock I can't use one in the big band some places, they get too nasty. My clone has a big power tranny and Deluxe OT. That's the only difference from stock but it increases headroom immensely, while still retaining the PR sound. You might consider upgrading the trannys. "fat stack" power tranny. Be sure to get a kit with good pots and only Switchcraft jacks.
My belief is the phase invertor scheme and bias trem are what make the PR sound a bit different than a DR. But if you already have a Deluxe try plugging into the normal channel, it get's closer to a PR gritty tone.

 

That‘s a cool clone. Since I need a european transformator that‘s an option.
But on the other hand I think Leo‘s got it right with his design. Even the small 10“ speaker is one part of the Princetons magic mojo...

 

I put a GA 10SC 59 in my tweed vibrolux clone and it is fantastic

 

TAD stocks a fat transformer.

https://www.tubeampdoctor.com/en/sh...erb_Amp_Champ_Vibrochamp_all_AA764_models_103

 

As well as the fatter PT, TAD also supplies an uprated OT that also fits the Deluxe reverb.
https://www.tubeampdoctor.com/en/sh...for_Fender_Deluxe_Reverb_Princeton_Reverb_154

 

As long as you don't utilize the pull switch, the amp acts like it should as normal. On my Deluxe, it would nearly kill the reverb if you used the switch.

 

I like 12" fine.

 

I like them too- a 12“ speaker is best choice if you’re playin‘ a Princeton on Stage, better spread and more 3-D. More power, more mids.

But at lower volumes (recording, home) nothing beats the dynamic response and sweet frequencies of a 10“, at least in my experience.

 

PR can be small for some applications. I installed a Mercury OT, sent more voltage to the Phase Inverter from the filter cap, solid state rectifier, and 12” Jupiter alnico speaker. It’ll keep up on any stage and still has the PR signature tone. But at home or a quieter setting total stock is perfection. Or you can use multiple PR’s live stock to compensate for volume or too much breakup. Either way they are one of the most beautiful amps ever. They are not like anything else Fender makes as mentioned above on the PI and bias.