Questions for 1966 Princeton Reverb Quest to get the Jim Campilongo tone

[cs1botasky]

Hello guys!

I am after Jim Campilongo’s tone and recently pull the trigger on a 1966 Princeton Reverb.

I found the reverb on the amp is lush and full sounding, which I like but the amp itself sounds a bit too trebly and brittle to my ear even I swapped the speaker with a vintage C10N. (When the original speaker was there, the trebles are unbearable…)

I was told the transformers and all caps are original except filter caps are replaced. Since the PT is a 125P1B, I believe it’s original, although I have seen a very reputed shop selling another 1966 PR which they claim it’s original but the PT there is a later era (and supposedly a better) PT, a 010020. Should I find myself a 010020 to replace the PT and would it change the sound of the amp?

Do you think I should replace any caps?

I must admit I don’t know anything about caps and have very little knowledge about tubes. (Please bear with me, when I look at the gut pictures, I have no idea which cap is which…)

I have heard Jim Campilongo have RCA 12AX7A in his Princeton Reverb before he switched sides using JJs. But I am not sure which valve(s) he was referring to when he put the RCA 12AX7A.

The tubes that came with my 1966 PR amp are:
V1 Preamp RCA 7025
V2 Reverb Telefunken ECC81/ 12AT7
V3 Reverb Sovtek 12AX7LPS 2009
V4 Vibrato/Phase Inverter Sovtek 12AX7LPS 2009
V5 Power Tubes RCA 6V6GT
V6 Rectifier Sovtek GZ34

To my understanding, 7025, 12AX7, 12AX7A and ECC83 are the pretty much the same but the 7025 and 12AX7A are supposedly quieter, but I also heard 12AX7A breaks up earlier compare to 7025. Is that true and is that the only thing I should concern when I swap out my RCA 7025 to a RCA 12AX7A?

Do you think I should swap out the V1, V3 and V4 for NOS RCA 12AX7As?

I also heard he once favored Brimar 6V6GTs but I have heard Brimar 6V6GT would sound a bit lean compared to RCA 6V6GT in Fender amps, do you guys agree?

I also did a little bit more research around on Jim’s Princeton Reverb(s) and I hope they would help others who are also a fan of Jim Campilongo:

1) He installed bias pots to bias the 6V6s in his SF PR at 30s and put the Celestion G10 Vintage there but not sure if he biased his BF PR the same.
2) He tried C10N in his SF PR but seems like he wasn’t really like it.
3) He has a PR (not sure BF or SF) which has a JBL 120 speaker, however which series (D, E or K) is unknown to me.
4) His C10N is reconed
5) He did the “$40” blackface mod on his SF PR but I don’t know what the mod actually is. If anyone knows, please share
6) Tried 12” speakers but prefers vintage Jensen, and he prefers C10 (N, P and Q).
7) Seems like his SF PR (w/ 6V6s biased at 30s, JJ tubes and Celestion G10 Vintage) is his main gigging amp.
8) He turns his amp volume on 10, Bass on 10, Treble on 7 but his guitar’s volume is not on 10.

One last question, when Jim biased the tubes at 30s which will make the tubes last short. Is he preferring to the power tubes (6V6s) only? Or is there something like biasing other tubes (preamp, reverb, rectifier…etc) hot as well?

I am just thinking, if it’s only the 6V6s, may be a mix of JJs (cheap and reliable) power tubes and NOS tubes (which is not biased hot) at other valves could yield the benefits a great sounding and economically maintainable amp (since only have to put in new JJs)?

Thanks very much for reading the post. Really appreciate your help and hope some of the infos I found would help!

 

[Lowerleftcoast]

The red circle is the cap can. These are the filter caps you say have been changed. I can't tell from the photo. Does it look like the solder has been disturbed indicating the cap can was indeed changed?

The green line is the 6V6 bias cap. It should be changed immediately, if not sooner, imo.

The yellow lines are the preamp tube cathode caps. (Sometimes Fender has another preamp cathode cap in the yellow circled area. I can't see one there but maybe you can.) Imo, these should be changed. There are others on TDPRI that would only change these if the caps proved faulty.

The pink arrow is pointing at a resistor. Does the resistor look burnt?

 

[Jon Snell]

In my opinion, you should fit the correct valves. A 7025 is a very noisless ECC83 or 12AX7, nothing more.
You speak about volume control settings ... this is all subjective. How hard do you/he hit the strings, after all a guitar is actually a percussion instrument. How much magnetism is still charged in the pickups, that governs the output voltage ... how was the guitar wired, what value pots etc etc etc.

A 6V6 is a 6V6. A 6V6GT is a 6V6GT slightly different specs to a standard 6V6.
A JJ may be made in China, it may be made in Ukraine, who knows without experienced eyes.

A 12AY7 will give you the lift of a 12AX7 and more head room than a 12AX7. A Sovtec 6P6S is a high grade 6V6 and will out perform most cheap junky JJs.

Looks to me like the capacitors are original. I suggest you have then leak tested and changed if required. There are many makes of dual capacitors available so don't let an unskilled person try and tell you different. I keep 20u - 20u in stock as I do 8u - 8u for the VOX AC30s. It is always best practice to keep things as they were designed.

 

[Lowerleftcoast]

I have heard Jim Campilongo have RCA 12AX7A in his Princeton Reverb before he switched sides using JJs. But I am not sure which valve(s) he was referring to

The most influential preamp tube will be the first one, (V1). I am a fan of *rolling tubes* (trying different tubes) Let your ears be your guide. Chances are you will find JJ 12ax7 to be gritty and Electro-Harmonix to be smooth to the ear. Mullard reissue are getting some love. You have to find out for yourself. There are other tubes that fit and work in the 9 pin Noval sockets. What is best is up to you.
I would buy a couple different tubes and rotate into the different sockets. Also try a 12ay7 for V1. Heck you can move the tubes you have around to hear if there is a difference.

V2 is a driver tube. It is like a power tube but it drives the spring reverb. A 12AT7 is a driver tube. A 12AX7 will work in V2 but may not last as long. A 12AT7, on occasion, is favored in V1. I have not found one I like in V1 yet, but others have. It is OK to use a 12AT7 in V1. It won't hurt anything.

I have heard Brimar 6V6GT would sound a bit lean compared to RCA 6V6GT in Fender amps, do you guys agree?

Sometimes a power tube will change the character a lot. You will not know until you try. To me, most of the 6V6 sound as expected but on occasion there are duds.
My observations...
The JJ 6V6 sounds more like a 6L6. That is not a bad thing, just different. It is a strong tube.
The TungSol 6V6 Re-issue has several TDPRI threads reporting *red plating* issues.
Sovtek 6V6 and 12AX7 are hit and miss sound wise.

when Jim biased the tubes at 30s which will make the tubes last short. Is he preferring to the power tubes (6V6s) only? Or is there something like biasing other tubes (preamp, reverb, rectifier…etc) hot as well?

That would only be the 6V6. The Princeton Reverb is unique. The hotter the bias is, the less vibrato can be heard. Double edged sword for this amp, if you like vibrato.

 

[Lowerleftcoast]

Should I find myself a 010020 to replace the PT and would it change the sound of the amp?

I wouldn't change the PT. Chances are a different PT will make the amp sound different.
FYI, the original Princeton Reverb power transformers are only rated for 70mA of current draw. The Princeton Reverb draws that much current. Attempts to *hot rod* the Princeton may not be good idea and pushing the 6V6 bias into the *hot* zone may not be a good idea. It can be voiced differently without taxing the PT.
A test for the PT. You should be able to put your hand on the PT when the amp is warm without getting burned.

 

[King Fan]

I'm impressed with your research. Good luck getting that Campilongo tone, tho. Your point about the guitar volume knob could be a big part of his secret; I've also heard he has super-low-output pickups specially wound for him.

OTOH, I don't know anyone else in the world (tho, heh, there are a few people I still don't know) who plays a PR with volume on 10. If I were going to try to get there, I'd want to do everything I could to 'un-hotrod' the amp. And before that, I'd be sure my amp was nicely and safely updated with new electrolytics. I heard Campilongo get "his tone" on a '68 CPR the year they first came out; tho his tech might have made some of 'his mods' in there, I'm pretty sure they didn't go inside and replace the electrolytics and resistors with old ones. Plus, if he can get it out of a CPR, that tells me his tone is more inside him than his amp.

Finally, as much as I believe tubes matter, and agree with LLC you should find a V1 and output tubes that *you* like, I think your chance of finding a set of particular tubes that give you someone else's tone is limited. Better to borrow their fingers -- though they may object.

 

[Back at it]

You’re going down a real deep rabbit hole in trying to match his amp but have at it if it’s what you want

the only way to truely get there is to have his tech match it but aside from that better to you your ear to get close without going crazy

rolling tubes in v1 is interesting and same with power tubes but my guess is you give him any similar amp and he will still sound like him so it’s not as much the amp but more him and his style of play

 

[LostGonzo85]

His secret is his fingers, his liberal use of the knobs on the guitar, and the countless hours he's spent practicing. You're going way to far down this rabbit hole IMO. Your speaker, tubes, and transformers are perfectly fine. He has great tone but - I say this as a fan - I don't think there's anything particularly mystical about it, and I don't think there's anything particularly special about his amp, his tubes, bias, etc. His idiosyncratic technical vocabulary is far more important when it comes to his sonic signature.

 

[Lowerleftcoast]

Yeah, yeah tone is in the hands...

There are several simple and reversible mods that can calm treble. Imo, the amp should be in good health before deciding to make an *improvement*. I am not yet convinced this amp is sounding like a Princeton Reverb should.

 

[Refugee]

You’re going down a real deep rabbit hole in trying to match his amp but have at it if it’s what you want

the only way to truely get there is to have his tech match it but aside from that better to you your ear to get close without going crazy

rolling tubes in v1 is interesting and same with power tubes but my guess is you give him any similar amp and he will still sound like him so it’s not as much the amp but more him and his style of play

From what I've seen is he always plays in stereo. So, you'll actually need yet another vintage Princeton Reverb. Like Back at it said, "Real deep rabbit hole..." Good luck, though! Seriously.

 

[Ronno25]

Just to throw this out there - I’ve owned two vintage - one sf and one bf - Princeton reverbs, as well as built my own clone. They have all sounded too bright to me in the upper mids. It annoys me and I sold the two vintage ones I owned because of this. When I built my clone I put in a high-cut pot mod. This did the trick for the most part.

I’ve owned many other vintage amps of the blackface/silverface variety and never found them too bright, just the Princeton reverbs. So you may be reacting to something inherent in the circuit. That is of course if your amp is healthy as mentioned in previous posts.

 

[SnidelyWhiplash]

I learned a long time ago that chasing your heroes tone can be akin to falling down a rabbits hole. Can be very expensive with no guarantee of success.

 

[King Fan]

It's kind of ironic we're trying to figure out how to get 'good tone' out of a vintage PR, since IME it's fairly hard to get bad tone out of one.

Other than 'the right speaker' (tho folks like everything from vintage Oxfords to silver-domed 12s, really bright or spiky speakers aren't a great fit) and a renewed cap can, the one ingredient I might have suggested was *not* to run the volume on 10, or (usually) the treble above 7.

I have nothing but respect, tho, for those who've had vintage PRs in good shape that were too bright: a) your ears are good ears, even if they're not mine, and b) lots of other factors come into it. In fact, I mighta said that the PR may be less perfect for a bright Tele bridge than some amps. But lol, Campilongo fans, does he use the bridge position? His great stuff seemingly exists to upset PR conventional wisdom.

 

[corliss1]

You know what he plays when he travels? Whatever 65 or 68 version of a Deluxe Reverb or Princeton Reverb the area can get. And he sounds just fine.

Get the amp serviced and go from there, but it's gonna take more than that amp and a Telecaster to get that sound.

 

[cs1botasky]

Thank you so much everyone for your kind help and suggestions. I am not very active on forums but you guys are still very helpful, really appreciate it!

I have checked Jim Campilongo's site again and found the magnet in the picture of his "C10N" seems a little bit smaller than usual C10N and seems like only Fender labeled C10NS were came with later BF Princeton Reverb. I guess may be Jim's "C10N" is actually a C10NS?

And I would like to thanks for all the suggestions for explaining what kind of caps in my amp and suggesting a check up and some replacement. I will surely bring my BFPR for a check up and may be I am not satisfied with the sound is only because the amp has to be serviced.

I would love to show more "gut" pictures of the amp, but the gut picture above was from the seller. Since I don't know much about repair, I dare not to pull out the chassis myself. But I will take some pictures when I see bring the amp to my amp tech.

For tube replacement, I am going to order:
2 x RCA 12AX7A grey plates
1 x RCA 12AT7WA
1 x RCA GZ34

I guess a whole line up of NOS RCAs won't be too bad but I guess I might try out some NOS JAN Philips or Sylvania tubes later

For the "fingers" vs "gears" thing, I guess it's a combination of both. I am a fan of Joe Pass and I used to listen a lot to his records. I somehow found out that I prefer his late ES-175 sound than his early ES-175 sound, nonetheless, an incredible guitarist. And then I also found out his early ES-175 were from mid 60s (1964 or 1965?) and his late ES-175 were custom built by Gibson featuring a single humbucker flush right after the end of the fingerboard with a little bit thinner body depth. I guess when we like the whole sound from a musician, the whole sound can be split into 2 parts, one were made up by his gears and other made up by his "fingers". As long as we know which part of the sound we like, it will be easier for us to narrow down our choices to approach.

Thanks for pointing out that Jim actually uses the PR reissues, I thought he endorsed them only I actually also have a silverface 1973 Princeton Reverb and tried a Celestion G10 Vintage there, and the speaker does give the throaty mid sound with a tele which is an essential part of Jim's sound. I guess may be Jim also has the Celestion G10 Vintage in the reissues, so the reissues can retain that signature throaty mid of Jim's tone?

For the rabbit hole thing, I agree...in case I can't really get a sound similar enough (for my own standard) after a couple of more try, the right choice is to move on, getting deep inside the rabbit hole is such a torture

 

[LostGonzo85]

Thanks for pointing out that Jim actually uses the PR reissues, I thought he endorsed them only I actually also have a silverface 1973 Princeton Reverb and tried a Celestion G10 Vintage there, and the speaker does give the throaty mid sound with a tele which is an essential part of Jim's sound. I guess may be Jim also has the Celestion G10 Vintage in the reissues, so the reissues can retain that signature throaty mid of Jim's tone?

I mean, maybe, but there's a video on Fender's site where he's demoing what he have to assume is a bone-stock PRRI with the Italian Jensen C10r everyone seems to hate, and... he sounds like no one other than himself.

Similar with with '68 Custom video he did for Fender. Sounds exactly like him with the stock Celestion speaker that many on forums have written off.

 

[cs1botasky]

I think you mean this video, his control on the overdriven sounds is amazing:


I really have no idea how he was able to pull that amazing sound out of the reissue above and the 68' PRRI in another video...I tried both 65' and 68' PRRI at my local store before and I couldn't recall there was anything similar to the sound in the video(s)...

May be I didn't turn the Volume and the Bass up to 10 back then, or more likely it's because I am not Jim

 

[Back at it]

10 is the secret, controlling volume and crunch from the guitar

and his hands

 

[beninma]

There are plenty of videos where he gets his sound out of a stock RI amp... you are way down a rabbit hole.

I think the only real magic is he puts the amp on 10 and supposedly also dimes the Bass which seems like insanity to most people who plug into a Princeton Reverb.

He does online lessons.. I think your time/money would probably be way more effectively spent taking some lessons from him.

I have learned one of his songs and actually playing his style is a huge part of it. I didn't take a lesson with him but my guitar teacher did so had a pretty good handle on how to play it correctly. You will sound more like him playing something he wrote the way he plays it with the wrong amp than playing something different with one of his personal amps. Heck I don't even think you even need a particular Tele to sound like him if you're playing like him. You just need a Fender style headstock.. you can't pull some of his tricks on a 3-per side headstock like a Gibson.

 

[speedy mcfeely]

Doesn’t Jim also turn the bass all the way up too? That may be the missing link? I’m sure you’ve matched his settings though? Jim is a wonderful player and really understands his tools. He has spent decades with that Tele and Princeton rig. Nothing can match that level of experiential knowledge of a very specific sound.