Repairing a VINTAGE Silverface Fender Princeton Reverb [Full Service+DEMO]

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We take a close look at a great vintage classic amongst guitar amps, the Fender Princeton Reverb, covering tubes, capacitors, sockets, bias, and what not! Even in today's modern in-the-box realm of recording, the Fender Princeton Reverb, especially the vintage ones still stand a solid ground in recording electric guitar!
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In this complete repair service we discover that it's from 1976 and in good shape, but has probably has never been serviced before. We change out the electrolytic capacitors, and also end up replacing the octal tube sockets after an attempt at re-tensioning the pins in the original sockets. These were worn-out, unfortunately.
0:00 Introductie
0:21 Visual Inspection
2:35 Disassembly
7:01 A Service Plan
8:43 Happy Soldering Time!
15:42 Surgery Recap
16:08 Cleaning Pots & Tube-Sockets
22:02 Bringing it to life
26:45 Output Tube Bias
33:25 And more soldering!
34:19 DEMO
We are lucky: This PT is a double-120v example and the JJ-5U4GB miraculously gives us the right voltage for a newly installed set of JJ-6v6 in the original non-adjustable fixed bias setup! Too high current draw could cause low plate voltages but it's good that's not the case. A GZ-34 takes it closer to the given value on the schematic anyway but the amp works great in this conservative setup. In this video I'll show you how to calculate the bias in these.
The original Blue coupling capacitors also test fine and are not leaking (yet). While the amp might benefit in the future from a preventive replacement, it's nice that it's further fully original and working great.
We do modify the tremolo as it is a very easy and reversible mod. The original value of 1M didn't quite cut it, even with the intensity on 10. This is a common mod.
Gotta love these old Princetons, which aren't critically altered since the blackface era. When pushed a little and played with the right touch it can give you a wide range of great guitar tones with just your attitude and electronics on your guitar!
May it please you, more tech-mumbling content is on the way!
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[@TwangThang57]

Great work and best explanation of biasing I’ve seen! Great playing as well!!

[@bricknboxer]

The demo at the end with the tele is awesome. Fantastic tone. My PR is just a bit older and is a lifetime amp for sure. Thank you!

[@meesterprofe007]

Sounds real good .....sweet amp😊

[@amonterrosomusic]

Great video man 🎉

[@doublechinmask3744]

I dont know why I am watching this.I can barely change a light bulb. Anyways,I really liked your video.There is something calming watching people fix amps and set up guitars.More of these please 🙂

[@giulioluzzardi7632]

Good job, glad you replaced those wonky sockets!

[@macintune]

Sparkle 😊

[@AldoSpadaroOfficial]

Is what it does!

[@lionscircle4700]

At 16:40 deoxit is sprayed into the tube sockets. I'm not sure that is best practice. I think isopropyl alcohol is a better cleaning agent as it will 100% evaporates out. Those sockets remain glossy/shiny after the deoxit spray suggesting that something was left behind for perpetuity. Tube sockets should look clean and dry. Thanks for the video.

[@tiborrisko7349]

Very cool! Amazing tones man!

[@i3oosted]

Clear and concise, perfect video. Thanks for posting.

[@oicsaywhat]

Sounds beautiful! Great job and thanks for explaining the details

[@enzodepaola6160]

Ciao Aldo, Perfect video and very well explained process. Really appreciate it. I love my ´66 Princeton Reverb. By the way , the telecaster authority the Princeton is perfect . That is my set up , ciao e salute

[@theheavylemons]

Sounds unbelievable with that Telecaster

[@jochemjonker3362]

You are Dutch,i prepose(you sound Dutch). Great video and explination on working on this amp. Soon i get a friend over,to inspect his Fender Princeton reverb: it got serviced years ago,so maybe some capaciters are already replaced.It needs service on the pots(got scratchy) and check the tubes.Maybe the speaker is gonna replaced with a JBL E 110.

[@jamesamason6182]

great job thanks !

[@joppepeelen]

yeah the green wire is a nice cold joint :) except for that nice!!! its amazing how simple they are.

[@Mauitaoist]

Wonderful video I'm fixing a Princeton reverb right now the 1000 Ohm resistor by the center tap keeps melting well we'll see if I can fix it thanks again

[@zjokka]

You could measure the voltage drop over the OT live, but use an alligator clip. Even with this multimeter, you would have gotten two decimals, which really matter... If the voltage drop was actually 4.4V dissipation per tube would be +11W. Great video still!

[@BadChizzle]

An amp that sounds that good with speaker face down on a table is gonna work out just fine.

[@AldoSpadaroOfficial]

There's just something magic about a vintage Princeton amp. They just got it right!

[@BadChizzle]

Aldo Spadaro I’m hoping same to be true with the reissue, as I just got mine fedex. Ha ha ! Luckily I have the skills and know how to make it right, of it isn’t. Thank you for your kind response. ✨

[@AldoSpadaroOfficial]

@@BadChizzle Cheers, mate

[@adamcarswell1287]

@@BadChizzle I have a '73 Silverface Princeton and the '65 RI. I love them both but there is something magic about a dependable vintage amp.

[@TiborRisko]

looks like this amp survived a gunfight ;)

[@joppepeelen]

well there has been some work done, in terms of ceramic caps. i dont think they had those back in the day :) but might be that they are not caps at all :) the discs i mean :)

[@AldoSpadaroOfficial]

Yo Joppe! Well, they did, those disc caps were already made before WWII I think. The ceramic disc caps in this amp are the original ones. These are 250pf as a treble cap and some 0,01uf's in the tremolo section. They are pretty sturdy survivors usually but one might replace them with Mica's or something like that.

[@fin.d7725]

Is the volume knob turned down at all on the tele in the demo?

[@AldoSpadaroOfficial]

Hi Fin, It's a while back, I honestly don't remember. ;) Might be turned down on the amp but using amp's dynamics for cleans.

[@rickeads6160]

By chance could you be so kind as to list the mfg and specs for the electrolytic capacitors that you replaced? Also, what the original rating for those components was on the unmodified setup?

[@AldoSpadaroOfficial]

The Can Is a 4x20uf, the bypass caps are all 25uf@25v on paper. I used 25uf@50v as they are more sturdy. The 1st bypass cap sees voltage on the high side of the rating so also a safety measure. Bias cap is 100uf I believe, the original rating is 50v but the voltage there is on/over the limit, so also safety measure. Hope that's clear, have fun and good luck, mate! Gr,

[@curunduraj]

Hello Aldo. I'm not an amp repair guy but I found your video very interesting. I have not plugged in my 1970 Princeton Reverb in many years since it's not working correctly. The issue is very low volume that does not increase as I turn it up. I am the original owner and I am pretty sure it's never been serviced. I know I need to take it to a qualified repair shop but am just wondering if this issue indicates a likely cause? Thank you.

[@AldoSpadaroOfficial]

Ciao, by all means be careful, don't touch any of the electronics yourself before the filter capacitors are drained. Let's see, low volume can be caused by many things but if turning the the pot doesn't do anything, maybe the age and accumulated dirt in the amp grounds out the signal, either from the pot itself or the jack inputs. If there's sound the circuit still works. I would be interested in taking a look for you, but that would be complicated. Maybe look for a specialised tube amp tech, overhauling this amp makes it a great piece of gear. Good luck, regards,

[@curunduraj]

@@AldoSpadaroOfficial Thank you for the comments/advice. I'm actually taking it in for repairs tomorrow. I'll post an update when I get it back.

[@joppepeelen]

hihi or just short the caps if you want to get rid of them anyway ;) hehe

[@AldoSpadaroOfficial]

Let's do a capacitor blow-up party someday!