1967 Fender Princeton Reverb Amplifier Restoration: Part 3 of 3
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- Опубліковано 26 гру 2024
- In this third and final video of the series, the restoration of a 1967 Fender Princeton Reverb amplifier is completed and the functions of the amp are tested. Topics covered: reverberation rank repair, cabinet interior and exterior, and a chassis review. Be sure to watch these three videos in proper sequence, to maintain continuity. Thanks for watching !!!!
Well, that was very satisfying to watch the old girl get a makeover.
You're a magician, Uncle Doug. I had to go back to video #1 for a before and after look. I'd never believe it was the same amp. Amazing job... esp on that grille cloth.
Thanks so much, Bob.
What an awesome and careful job! Glad to see that bad boy up and running like it was '67. Thanks for sharing!
+feLine hAru You're welcome, FH, and thanks for the very nice comments.
Nice save uncle Doug, well done!
Thanks, Kevin :)
LOVE the Tremolo mod! And the reverb kicks bootie.
Thanks, Dave :)
I did your addition of two 1 meg resistors to boost my tremolo. It works great. I now have 3 Princeton Reverbs and love them. Great amps.
+Bbendfender I'm glad the mod worked for you, Bb. Three PR's ? You're a lucky guy :)
She's beautiful again! How satisfying to find a neglected amp and to be able to restore it so professionally. Bravo Maestro.
Thanks so much, Stony. If you'd really like to see dramatic improvement in a really beat-up, neglected amp, please watch my video on the 1947 National Amp. I think you might enjoy it :)
I just now came across this 3 video series on the 1967 Fender Princeton Reverb Amplifier Restoration and your YT channel Uncle Doug. I must say, you sir know how to do it RIGHT. You show what is so often lost today, Real Craftsmanship. I am very impressed with your attention to detail in keeping this original but correcting and slightly modding needed repairs and keeping it all very clean. Well done Uncle Doug! Saving a very fine older Fender amp to play on for many years to come.
Thanks so much, TR. I'm glad you enjoyed the series.
Just came across this today. Great to watch and learn. I also have a AA764 PR with a date code on the reverb transformer of May 65 and "HO" stamped on the tube chart indicating August 65. It has the "Fender Elect. Instr. Co." wording on the right. The year of transition. Great little amps, along with the Deluxe Reverb, my 2 favorites.
I'm glad you enjoyed the video, Dan.
Great Job restoring this amp. Princetons are great amps.
Thanks, BD. I totally agree.....Princeton's and PR's are among Fender's best.
Check out my tweed demo's on my page. I really like some of the mods you do with the tremelo and reverb.
You are my kind of amp tech dude, with that tremolo magic! And you are an ace clean up person, good grief. Great job!!
Thanks twice, TT :)
Great set of videos on this amp.
Thanks, Susan :)
All that expert work and thought into this amp makes it priceless.
Thanks, Bct :)
Oh yea hope you can find that 12AX cover, otherwise all is for naught.LOL
Well done Uncle Doug! It was great to watch all the details of this amp you addressed including simply cleaning it up! It's nice to know there are other toothbrush wielding, tolex cleaning, solvent applying, staple removing. clear coat spraying, car wax using people out there! Your mod on the tremolo was great. Love the perfect choice Jensen too and the resistors applied to ground to protect the replacement power tubes. You must have spent a lot of time on this. Results are fabulous. Hats off and thumbs up to you!
Thanks so much, Bruce. Rusty and I really appreciate kind, supportive input...and your comment made our day :) As you said, it's good to know that we are not the only obsessive-compulsive amp restorers out there. After the video was completed, I modified the bias voltage supply to be adjustable, as in the Deluxe Reverb, and described the process in a video that you may find interesting. Thanks again for your very nice comments.
Uncle Doug I know almost nothing about amps except I can follow a wire from where it comes from to where it goes! Your videos are thankfully changing all that now. The most ambitious project I ever did was to gut a Hammond Maverick lower end home organ to take the rotating drum mechanism, (kind of like a poor man's Leslie), and mount it in a cabinet with the speaker firing upwards into the rotating drum. I isolated all the preamp signals and narrowed it down to three that had distinct tonal qualities. Used the Hammond logo and some of the switches, used the power amp and threw away all the organ keyboards. The worn out organ was given to me for free. I call it "The Twirly" and it is something I'm proud of. I even used a sewing machine pedal to control the speed of the motor. Doppler effect glory! Works great for home and studio.
By coincidence, Bruce, I also built a compact Leslie speaker unit with a speed control. I have a video of it posted on my YT channel. It really is an impressive effect.
Shame about the old reverb unit... and a very clever solution to making it "like new". Bravo!
Have any psychedelic grill cloths come through your doors? I suppose it's heresy to the purists, but back in the day, I used to see The Grateful Dead, and also Jerry Garcia- many of their amps had what looked like tie dye speaker cloth.... I always loved that touch... but of course, I love the pristine version even more.
Since I only work on vintage gear, I don't see any crazy grill cloths, Brad.....but no doubt one will appear in the near future, just to prove me wrong :)
What a great restoration and fantastic sounding Princeton reverb!! Your knowledge of amps is mind boggling.
Thanks so much, William.
Wow, you hit it out of the park. Man that sounds smooth as silk. I’m putting a gold star by your name. Now I’m sure the Princeton is what I’ve been looking for. Stay safe UD
Thanks, OG. Princeton Reverbs are one of Fender's best amps ever.
old school tube amp skills are rare in today's shops. the information you share is solid gold sir. i would like to thankyou yet again for such a wealth of information. wish i met a teacher like you in my younger days as i would have likely soaked up so much skill. that being said theres nothing like starting today before your a day older tomorrow! !!. and any thumbs down should be ground into dogfood for Rusty. cheers again from victoria bc canada :)
not that rusty would eat it. i remember the high end food test. haha !!!
You're welcome, Scott. Thanks so much for your very kind words. You're right......it's never too late to learn a new skill. Ditto on the naysayers, who voice their disapproval anonymously and without explanation.
Amazing restoration work; one of the most extensive I have ever seen.
+John Cunningham Thanks, John.....glad you liked it :)
I have the -amp version(non reverb princeton) of this and a model 26 woody.....they need service for sure. Very cool video...thanks so much.
It was our pleasure, P. Message me on my FB page Uncle Doug's Vintage Amps when you're ready to get them repaired.
@@UncleDoug Very cool, found your paged and liked....I'll send a pic of them. Thanks again.
I very much enjoyed this video. Parts 1 & 2 also.
We're glad to hear that, Michael.
Just caught this veritable blast from your past Uncle and what a great blast it was too. Such an iconic sixties type sound coming out of that wee smasher! The Jensen speaker nailed it - just perfectly in sync with the amp dynamics and tone. Amazing! I wonder how this would sound with a nice warm overdrive pedal stuck in front of it? Awesome would probably be the case I would imagine. High esteem and appreciation as always - I'm definitely hooked on these great videos you produce and I have learned a lot of things that I didn't know or even remotely understand before - It's so cool. More, more, more please. Alex the K.
Thanks so much for all the great comments, Alex. There are more videos on the way :)
@@UncleDoug Oh Goody! Can't wait Sir.
Great restoration Doug! I like your dedication and attention to detail paired with healthy pragmatism. I learned so much from your videos already... I'll keep following.
Thanks, W&S. I'm glad you're enjoying the videos :)
Awesome Restoration
Thanks, Charlie :)
Thanks for sharing .....Im just about done with my 64 Princeton Reverb .....New speaker
baffle and done .....
Congratulations, Tommy. I hope it exceeds your expectations.
@@UncleDoug Question , What Thickness Baltic birch plywood for the baffle do i need to use ?
@@tommyfisher2430 I would say 1/2" thick, Tommy.
@@UncleDoug thanks Uncle Doug .
@@UncleDoug BTW
I picked up a Ragin Cajun 10 inch speaker it sounds fabulous in that amp
Awesome video. Impressive job overall and that was a miracle you performed on that grill cloth. Thanks for all the good info :D
Thanks, Zach. I'm glad you enjoyed the video and really appreciate your kind appraisal :))
Uncle Doug I recently purchased a 68 Super Reverb. It's all original except grill cloth/baffle, two speakers, and the filter caps. The bottom side of the chassis shows evidence of duct tape previously being used around the "dog house". The current filter caps(Sprague Atoms) in the amp have melted duct tape glue on them! LOL! Looking closer I noticed the screws to the dog house weren't original so I'm assuming the previous owner removed doghouse ->lost screws-> DUCT TAPE!!! I thought you might get a kick out of reading that. If I can work half the magic on this amp that you did to your 67 Princeton then I'll be in good shape. Lexol on the tolex and car wax on the plate have cleaned up the appearance quite a bit. Thanks again for the tips!
You're welcome, Zach, and thanks for the update on your SR. Over the years, I have seen all sorts of idiotic quick-fixes, including using wood screws and even nails instead of machine screws, but the classic example was the guy who replaced a bronze bushing in a jukebox by hammering in the brass base of a shotgun shell. Good luck with your restoration !! :))
Uncle Doug So I tried to clean the duct tape glue residue off of the chassis with not much success. This would be much easier to do if I wasn't worried about scratching the chassis. I'll give it a go again next weekend. Do you have any advice on how to remove duct tape glue from the chassis? Thanks again for all the info. I've watched this Princeton Restoration series 3x now :D
Zach, lacquer thinner will remove just about any residue, but you have to be careful with it since it also melts plastic and dissolves paint (and your liver). A more gentle chemical to remove tape residue is WD-40. Carefully spray some on the residue and let it work (about 15 minutes) to soften the dried glue. There are some products on the market made specifically to remove tape residue......but I've always had good luck with either WD-40 or lacquer thinner (the last resort, but be careful !). Good luck.
Your three videos where very professional. Excellent job on the Princeton. I have , I believe, a 67 or 68. Says Fender Elect. Instr. Co. underneath the Princeton Reverb-Amp, all original, only reverb work and power end plug replaced. All original tubes. Would love to have you look at it! Very well done restoration!
Sir,
Another in a great series of videos.
Please keep them coming.
Andy W.
Thanks.....and we will, Andy. It's always good to hear from you :)
thanks for these vids, very informative! Thanks also for the tip on the Jensen speaker... I had two twelve inch Jensens in my 1967 Kustom 100 (they came stock with it) and I have never had speakers that great since then.
You're welcome, Flag. Yes, the vintage Jensen's were (and still are) wonderful speakers. Keep an eye out for old speaker cabs that may contain some of them, sealed up tight and well-preserved, just waiting for transplantation :))
Thanks for your positive assessment of my videos, Ron. I really appreciate your time, interest, and input. I would love to see your PR, but based on your icon photo, I have a feeling we are many miles apart (I live in the desert Southwest). However, we definitely share a common love of the blackface Princeton Reverb......IMHO, for its size, I think it's the best amp Fender ever made. Thanks again !!!
wow, unbelievable restoration work!
brian foley Thanks, Brian. Glad you liked it :)
You do very nice work. Very informative videos. Thanks.
You're welcome, Srv. Glad you enjoy the videos :)
I'm looking at other old amp restorations from your channel :) I really like the pace and deep explanations. Great stuff!
I've had to do some restoration on flat black spray paint on grill cloth before and I used the method you did and then washed with light soap and hand brush. Worked pretty good.
Man, you did a very nice job on this restoration. I always learn from your videos. Thanks.
You're welcome, Bbend. Removing the flat black paint was definitely a miserable job, but the old, original grill cloth just looks way more natural on the amp than a brand new, shiny grill cloth would. I think it was worth it. It's good to hear that you are enjoying the videos. Thanks for watching !! :)
Uncle Doug I bought a '61 Concert in white tolex that had been hand brushed black. It was a tough job but I made the amp look original when I was finished. In fact the amp received special attention in one issue of Vintage Guitar and later the Vintage Guitar Price Guide. It was a one of a kind.
I'm a great fan of early Fender Concert amps, Bbend. As I recall, Webb Music had Fender produce a limited run of Concerts in white tolex back in the very early 60's. If you can remember which issue of VG the article was in, I would love to read it.
Uncle Doug Doug, the Concert I had came from Webb Music. It had a sticker on the back of the chassis. I have a '65 Pro Reverb that also came from Webb Music and I live in Texas. I'll have to check out the VG issue.
Uncle Doug Doug, the VG issue with the Concert I had was Nov. 1997, with Pete Anderson on the cover. The amp is now back in Calif. just a few miles from Webb Music, where it originally sold. As always, I now wish I had kept the Concert.
Had a great time looking at this series. Thanks for taking the time to make it!
Great job! And I like your tremolo modding as well, much better than the original.
Thanks, A :)
That was great to watch, even for us non-techies. My only concern is that you used the same exact number of staples as were originally used on re-attaching the grill cloth. Otherwise, will have to give it a thumbs down as it will never sound the same. Seriously, great 3 part series, happy to see a great amp brought back to life.
Thanks, Mike. Yes, I carefully removed the original staples, cleaned, polished, and straightened each one out, glued them together in a line and then placed them all in a stapler so I could use them to re-attach the grill cloth. I'm just kidding. Glad you liked the video :)
A superb restoration / resurrection and I'm loving that new reverb, although two or three would probably suffice! More power to you sir.
Thanks so much, David. Glad you enjoyed the PR restoration. Re the reverb, I guess it's like horsepower and money.....it's always good to have more than you need :)
Thanks, Ed. I really appreciate your kind words.
Thanks. I'm just about to do the same job on my Silverface Vibrolux Reverb-Amp. (I just bought a brand new "Fender American Vintage '52 Telecaster" and I need my old amp to be top notch!) You had some great tips and advice in there. Cheers!
You're welcome, John. It's great to hear that the video was helpful :)
Young love for a demo *AWESOME* !
Glad you enjoyed it :) Sonny James rules !!
Thanks so much, MYT. On my own PR, I did replace the lousy, original cord with a 3-wire cord. I generally do this on classic amps only if the original cord seems damaged or unsafe. I have considered posting a simple, straightforward video on how to bias an amp, and may well do so in the near future. Thanks again, for your kind words and please stay tuned......
beautiful job ! very well done! love the extra megs. in parallel awesome effect to say the least . many warm wishes to you and your family there Doug ! Helps striaghten my thinking our every time i tune in to your channel. Blessings!!!
Thanks so much, Barry. Glad you liked it. Likewise on the blessings :)
3 great videos.. Thanks
You're welcome, Mark. Glad you liked the series.
Hey Doug, I thoroughly enjoyed your three installment 67 Princeton Reverb restoration videos. Great attention to detail, very informative and entertaining! I just purchased a 67, although in much nicer original condition than the amp you restored and having received it via UPS shipping found the reverb to be non-operational. Big disappointment to say the least. Hopefully it will be an easy fix. Thanks again and keep those videos coming!
You're welcome, JN. We really appreciate your nice comments. Check the diode in your bias voltage circuit.....it is often the culprit. Best of luck with your tremolo repair.
Full joy to watch. Thank you.
Tito Christo Polichronis Thanks, Tito.....glad you liked it :)
Thank you, Mr. Fitz.
What a great restoration! Plays as good as new and still has a lovely vintage patina to the cosmetics. When it comes to cleaning the Tolex, have you considered using Plexus instead of Armor All? Plexus was created to clean aircraft windscreens originally, and I find it really does miracles on Tolex. Pulls out more grime in a hurry. It costs about $15 a can, but really does a bang up job.
Mason Lamb Thanks so much, Mason.....glad you liked the video and the amp. I will try to hunt down a can of Plexus. Thanks for the tip :)
Thanks for the wax tip,I used the wrong stuff (stove and refregerater) on my 65 Bassman and took some of the shine off around the pilot light...I didnt want to repeat on my 63 Bandmaster..I hope you do more how too fix it vids..No wonder the Prince sounds so good,it looks like they have that first stage bypass (R) on the cap like a Marshall has
We appreciate your time and interest.👍
So do I, Bill :)
Hey Uncle Doug & Family, According to Richard 'Rick' McWhorter, and , as you may know this already, a few drops of WD-40 to the inside of the pot, help to re-hydrate the phenolic material, making better contact on the wiper. Awesome restoration, sounds great, I'm sea sick. Take care, C. P.S. Rick at All American Five Radio on YT.
I have indeed used WD-40 on pots, Cass, generally with good results. The majority of the spray evaporates leaving a small residue in the pot. I've even heard that spraying old speaker cones lightly with WD-40 will "rejuvenate" them....but I'm a little hesitant to try that one. Thanks so much for your nice comments regarding PR restoration :)
Really nice job, very interesting to watch you go through the process. Sure wish I had the electronic skills to understand the inner complexities but I don't. I never cease to be amazed at the original conception and design and production of these amazing amps. I'm assuming that every detail has been carefully overseen by the man himself, Leo Fender.
Thanks, 37. Watch the videos, paying close attention, and you will develop the skills you seek. We all started somewhere.
Thank you, David, both for subscribing to my channel and for your kind words of appraisal. Hearing favorable comments like this really makes posting these videos worth while. In addition, now that you have subscribed, you will be notified each time a new video is released. Welcome aboard !!
I had one of these and now I wish I had kept it!
I think we all have felt that way from time to time, MD :)
Thanks, Bob. By production sheet, do you mean the tube chart? If so, only about half of it was present (fortunately including the part with the AA-764 chassis number). Re the wax, I use Meguiar's Gold Class Liquid Wax. It really works well to restore and protect old, oxidized control panels, knobs, etc. Thanks for subscribing :)
I think you will like the Meguiar's, Bob, it's good stuff....and it works very well on cars too :) I try to include some tips in each video, so keep watching and (hopefully) there will be a bunch more.
Fantabulous!
Thanks, Chad.
Great job.
Thanks, Stew. I'm glad you liked the video :)
Hey Doug,
Enjoyed your 3 videos. Thanks! The grille cloth save was above the call for sure but came out okay. I would be interested in your opinion on changing out the 2-prong for a 3-prong grounded power cord and disconnecting the polarity "Ground" toggle switch and cap. Thanks again for capturing your adventure for us to view.
You're welcome, Eddie. I'm glad you enjoyed the videos. My feelings about power cords is, if the original cord is in real good shape and the amp has no hum and works fine for you, then leave it alone. If the cord is dried out, cracking, or the plug is damaged, then I generally replace it. Likewise with the hum-reducing capacitor and switch.....no problems, then leave it alone. Just be sure the amp has a proper-value fuse.
Greetings, Stargate. At your recommendation, I just took a look at the Pure64 amps and was pleased to see that they are focused on reproducing the tone of the Fender Blackface amps from the 60's. I need to read more about them. Meanwhile, you take a look at the Vintage47Amps dot com site. They're recreating the Valco amps from the 40's & 50's, with beautiful vintage style cabinets and great chassis design. Take good care of your Princeton, and thanks for the tip on Pure64.
Great job on this amp!
Congratulations on not giving up on that speaker cloth, definitely worth the extra effort.
Have you tried a black automotive paint repair crayon on that scratched faceplate? Together with the car wax you already use it may be worth trying.
I really enjoy your informative videos, and the sparkles of sarcastic humor here and there make them entertaining as well :)
Best regards, Stan
Thanks for the suggestion, Stan. I am not familiar with repair crayons, but will check into them at the nearest PepBoys. Rusty writes most of my scripts, so I will relay your appreciation to him.....once he quits chasing doves away from his food bowl :))
Out of curiosity, were you able to get hold of a black scratch repair crayon? I wonder if my advice was any good...
I found they work best on a thicker layer of paint, when the crayon material can fill the scratch (like on a car, for which they were made).
No rush, just if and when you try, please share the your opinion, be it good or bad :)
I have not yet, Stan, but it's on my shopping list for sure :))
Thanks, David. You may also enjoy many of the other 57 videos on my channel. I really hope you get a chance to check some of them out. Thanks again for watching !!!
Master class !
Thanks, D.
Awesome work!
Thanks, Ab :)
Fantastic!
Thanks, James.
@@UncleDoug You're welcome. Looking forward to watching more of your videos!
Awesome job man
Thanks, RW :)
exceLLent video of an exceLLent restoration .
Mike Barney: You comment had no Reply capability, so I'll answer it up here. Whenever I'm building a clone of a well-known amp, like the PR, I download a schematic and draw up a parts list from it, including transformer part numbers, cap values, tube sockets, pot values, etc. Additional information is also available on the lay-out diagram (also available on the Internet). Good luck :)
Your videos are great! Very informative and helpful.
Did you do anything with the AC cord? I have heard a lot of talk about bypassing the polarity switch on these amps and putting a three prong power cord on. Any thoughts on this?
The tremolo mod was genius, sounds great.
Next video could be 'pot cleaning' or 'amp biasing 101'
Again, thanks for your great work.
What a great restoration. ! You have mad skills and a wealth of knowledge coupled with patience and mild OCD. I know the world lives in a throw away mentality, but it's good to know that there are persons like you sharing their knowledge and expertise on UA-cam these days. I always look forward to your projects so that I can enhance my limited knowledge of tube equipment electronics or what new experiment at restoration you dive into!
Uncle Doug-I truly enjoy your videos.They are both educational and ocasionally hilarious!!!!-do you ever sell the amps you build and/or restore?
Greetings, Don, and thanks for the kind words. Yes, I occasionally "thin the herd", but only smaller amps that are fairly easy to ship. If you are interested in any particular amps, please send me a private message and we can discuss it.
Love the video series.....just purchased a 1965 BF Princeton. Haven't pulled the chassis yet, but everything I checked so far is original. Spent most of my non-playing time with soap, water and silver polish. On another note.......what is that song at the beginning of each video...driving me crazy...can't think of it's name. I also like the tremolo mod.
+Srblues1 Thanks so much, SR.....glad you liked the videos. Congratulations on a great acquisition. The BF PR is one of the all-time greats, in my estimation. Good luck with your refurbishment project. I often make up the tunes I play, but they are usually based on some familiar tune that's rattling around in my memory. I think this one is based on The Lonely One by Duane Eddy.
Hats off to you Uncle Doug, enjoy your videos so thanks for putting in the not inconsiderable effort.You have a talent for presentation to match your technical skills but your guitar playing eclipses both! What are some of those tunes you play in the demos? Especially the one you finish this vid with? Please tell.
Wow, thanks, GS. I really appreciate your nice comments. I believe the final tune was Young Love by Sonny James: ua-cam.com/video/c9vXQX4vP9Q/v-deo.html
Here is a really beautiful rendition of the tune, with simultaneous rhythm and lead......ua-cam.com/video/Von1LJL7hGU/v-deo.html
Very nice, Rusty wont get so jealous watching that one either.
Yes, that first guy had a pretty intimidating pup. I made sure that Rusty didn't see the video :)
Hey Doug I just found your site and have really enjoyed watching them. You remind me of a good friend and mentor here in the San Diego area George Runyan who like you can fix about anything. I was wondering if you're also a Radio Amateur? Seems like us you really like the tubes. As I had said in one of your other videos I came across a Fender Champ and with clean up and a little love its wonderful. I do need to change the Volume control pot as someone snapped off the shaft and also lost the knob.. Other than that it works great. Well back to your videos, really enjoying them.. God Bless
+Jake Blues Greetings, Jake. I did avidly restore old cathedral and tombstone radios many years ago, but moved on to audio tube amps, primarily vintage ones. Good luck with the VC pot replacement. Thanks for watching.
What a great video! You seem to have a wealth of knowledge, when/how did you start fixing amps? I hope to to start learning myself once I have a house with a suitable man-shed. I have an old Pro-amp viper I want to restore, but the last time I touched the insides, I almost died. :D
Greetings, Marc. I started working on jukebox tube amps about 35 years ago, quit for a while, and then started back up with guitar tube amps about three years ago. You can start learning at once.....there are all sorts of helpful videos and sites on the Internet that can bring you up to speed rapidly. Please watch my shock hazard video and some of my repair videos to learn how to prevent being injured while working in/on an amp chassis. Good luck !!!
I'm in the process of going through your video's now, they're all great, but there are a lot! It's like 'game of thrones' all over again. One thing's for sure, I learned the hard way not to touch a live capacitor with my bare hands..
The rule for working on a live chassis is to keep one hand in your pocket. You never want to complete a circuit with both hands.....the electricity will pass through you (and your heart) with sometimes lethal effect. Enjoy the videos, and good luck !!
Hi Uncle Doug. Great video. I did not recognize a word you use at 7:07 describing the cleanup of the cabinet. It sounds like “I amoroled it”. Could you please explain the final step in cabinet cleanup?
That sounds like my lazy way of saying "Armor All'd it", DS. Sorry for the poor diction.
Thanks for clarifying that. Your diction and articulation are very good. I have no problem to follow. I only did not know that brand. Greetings from Germany darkstar
@@_darkstar_ You're welcome, DS.
This is a almost perfect amp. But I prefer to add a 10k pot.in the bias circuit to controll the bias perfect. Knut Arne, from Norway.
Please watch my videos on converting fixed-bias amps to adjustable-bias, Knut, as well as videos describing the installation of a variable resistor in cathode-biased amps.
On the last pair of Jensen C10N speakers I saw on Reverb the manufacturer's stamps were on the basket just below the terminals.
I thought they were usually on the perimeter rim of the basket, D20.
i just found it a bit odd.
Great series of videos Doug. Silly question, you used 1Meg resisters on the tremolo, what was the wattage?
Thanks, Buzz. I generally use 1W resistors, but 1/2W would probably suffice.
Thanks for the quick reply.
You're welcome, Buzz.
Well I gotah say Uncle Doug you did a realy fine job on that amp reconditioning it. What did you do with it 10 years ago?
Thanks, Dwight It was sold or traded long ago.
i expected to see you update the 2-prong plug. perhaps i overlooked that part of the series.
Perhaps it was omitted from the video.....but it is always done.
What kind of car wax did you use..I wouldered how to clean my 63 did it have the production sheet on the inside of the cab Nice job too
1:45 Would installing a bias pot do the same job?
Yes, there are several ways to reduce the plate dissipation.
Another beauty renno, Curious about which reverb tank you used. Accutronics MOD?
PS enjoy hearing Sleepwalk and Walk Don't Run as well as what sounds like Young Love as test songs
My replacement tank of choice is the MOD tank Danny. Glad you enjoyed the demo.
@@UncleDoug Love your work! I have many of the Fender and Gibson amps you fix and I'm also a radio guy so love your work as repair and your dialog. Well done all around.
@@dannymarks988 Thanks so much, Danny :)
Looks like you've gotten side-tracked on your 'How To Cover An Amp With Tolex' series?
We've had some very cold weather that made my (45 degree) shop unsuitable for amp-covering, Vito, but I finally finished the video anyway. I'll be uploading it this afternoon (9 Jan). Thanks for asking.....:))
Nice job. The black covering looks great. What cleaner did you use.
This comment section doesn’t allow me to send pics to you. Can I email to you?
I generally use Lexol on black Tolex, Rick. Armor-All also does a good job, but Lexol actually softens and preserves the material. You can post photos on my FB page: Uncle Doug's Vintage Amps.
hello Uncle Dog, i'm enjoying your videos a lot. they are very educational and well explained. since a few years i'm building 5f1 champs, but recently i bought a princeton reverb kit don some measurements and was surprised that the high voltage coming from the 5U4GB is about +385Vdc instead of the 410Vdc on the schematic. without tubes the voltage rises to 495Vdc. is this normal? Also, is it advisible to just install the 5U4GB without any other tube inserted? Best regards, Benny (Belgium)
BAMPSANDPEDALS Greetings, Benny. Rusty and I are glad you enjoy our videos :) Measured voltages often vary from those listed on the schematic, and +385VDC is plenty. Yes, without tubes the socket voltages are much higher.....just like if you opened a faucet all the way with a plugged hose connected, the pressure would be quite high in the hose, until you unplugged the end and let some current flow. It's OK to operate the amp with only the rectifier installed; however, as you noted, the voltage readings will be higher than under normal operating conditions (tubes installed). Good luck from R & UD :)
By adding the 100 Ohm cathode resistors, you have changed the unit from fixed* bias to combination fixed and cathode biased, which is rather peculiar. I think you'll find that it sounds better if you replace those resistors with 1 Ohm (so you can measure the cathode voltage = current easily) and alter the bias voltage appropriately.
*Also note that this amp uses bias shift vibrato. Your extra-wide-sweep mod may not be very kind to the tubes, as the bias may be shifting from very low to very high.
+Tim Padrick Soon after this video, I deleted the cathode resistors and converted the amp to adjustable bias, just like its big brother, the Deluxe Reverb. This modification was featured in a follow-up video.
Hi Uncle Doug, Would the tremolo modification that you did with this amp be the same with a 1970 Princeton amp (non-reverb)? Thanks!
+Victor Skidanenko Yes, it would probably work for any Fender bias-modulating (i.e. non-photoresistor) tremolo.
Painters have Bob Ross. Guitarists have Uncle Doug.
I am flattered by the comparison, Tel :)
@@UncleDoug Just before the lockdown I had a 1965 Hohner Orgaphon 45MH given the overhaul by Andy Drinkall (Oldamps, Sheffield, UK - I have a bag with the 30+ components he replaced - facebook.com/oldamps/photos/pcb.2345391549050708/2345375369052326/ ) and, noting my interest in all things tube, said, "Have you watched Uncle Doug's channel? I think you'll like it." Then the pandemic/lockdown kicked in and, yup, subscribed.
As for my amp, Andy described it as 'a total b******d, almost forty hours work' - the power amp and pre/reverb tank/trem sections being at the bottom and top (respectively) of the amp making life difficult. There's a reason Stevie Wonder used it on that run of great albums from 70-79... it sounds incredible. Telefunken diamond ECC808s, ECC83 ECL86, EF86. My studio monitors are a pair of Klein and Hummel (Neumann) OYs from 1967, the first active monitor - bought with the Hohner for another £20 (the amp was £150, 2018, and I paid almost double for the overhaul). Got to hand it to those German engineers... good ears. ;)
Have you ever worked on an amp using PL84s in the power section?
p.s. I have four cats, two of which are strays that found their way to me... my last three cats ALL lived to 21+.
Greetings from Maryland, Doug!
I have a 1978 (I believe) Princeton Reverb in really good shape. I had a capacitor replaced earlier last year, but since then the amp has begun to produce a loud buzz/hum when turned on and the tone of a guitar plugged in is just awful; kind of like two high-pitched teslacoil screams at once, all squelched and nasally. Anyway, I'm trying to at least establish a diagnostic before taking it in to get potentially overcharged. Any suggestions?
Without being able to personally evaluate the amp, I am unable to provide any insight, other than to say that if the problem occurred immediately after having a capacitor replaced, I would suggest returning it to the tech who did the replacement and asking him to undo the damage he apparently caused.
Hi doug, I'm just curious. do you have any idea where a parts list of these princeton reverbs can be found?
I usually make my parts lists using the schematic, Mike. Good luck.
which Lexol product did you use? there are several, and I like your results.
It's Lexol Original Formula Leather Conditioner Preservative, BR, purchased from a local auto supply store.
and that cleans as well as Conditions?
Yes, it seems to do both.
A question for you UD:
On my ‘65 Princeton Rvb, I’ve been playing it with a replacement 10” Weber 8 ohm spkr along with running an external 12” 8 ohm spkr that is in a cabinet.
I never crank the amp up past 2.5 on the vol pot, but do use a Klon Centaur pedal ocassionaly for a bit of boost, but never overdriving the amp beyond belief!
Am I in any danger of of damaging the Princeton? I wouldn’t like causing harm to it...
Fender's internal/external speaker jacks are poorly designed. You should use either the built-in speaker OR an external speaker, but it's tempting to use both at one time, creating a lower impedance speaker load than optimum. At full volume, over time, this might cause some harm.....but at your moderate-volume use, you're probably OK.
@@UncleDoug
Thx for the reply U Doug!
In other words, do not run the PR (2- 8 ohm spkrs) at 4 ohms at ear-splitting volume ...?
Doug. I replaced the cap can on my '79 Princeton Reverb. No big deal but when I turn the amp on, it blows a fuse. I have a "short" somewhere and can't find it. Help. None of the schematics I found are the same as my amp.
If the short suddenly appeared when the multi-cap can was installed, it certainly implicates it as the culprit. Perhaps the new can has an internal short (not entirely uncommon). Best bet is to unsolder the leads to it and test between each terminal and ground to see if an internal short (i.e. any resistance that is less than infinite) exists. If you had an ESR meter, this could be done with all wires attached. Also, this situation would be much less perilous with a light bulb Current Limiter (I have a video posted). Check each of your B+ wires to be sure none is grounded. Dead shorts are generally easy to find, and you must find and eliminate it/them to avoid damage to your power transformer. Good luck !!
Uncle Doug Cap can checks out ok. I had recapped this amp several years back but did a hack job with axial caps just to get it going. Worked fine but yesterday I did find some leads to the cap can that were questionable, when I put in a new Mallory cap can. I'm not a tech but I've kept my Fender amps going for 30 years.
Uncle Doug Doug, what is the best method to check for shorts. I worked on the amp again today and could not find the problem. It is probably something simple but I need help.
I still think that if the short suddenly showed up when the can cap was installed, then the problem must reside somewhere in the can itself, or in the wiring. Perhaps there is a piece of solder shorting out a terminal. I would check it all out very carefully. I'm not sure how you ruled out the can capacitor as the culprit. Did you remove all the wires to it and measure the resistance between each of the terminals and ground? The resistance should be infinite.
Uncle Doug I checked the resistance between each lug of the can and ground. and it was infinite or "none" on my meter. I checked everything very closely today and even put a new cap in the bias circuit even though the other replacement cap checked out ok. I visually checked for any grounding problems. Made sure my work was clean and neat (for me at least). Still popped every fuse I put in. Those fuses are getting expensive. Is there anything to use besides a fuse that I might just reset?
At 25 seconds: It sounds like you wired the Reverse Zoom Auditory Safety Alert (RZASA) on your camera backwards. It is giving the safety warning to those nearby when zooming forwards. Or maybe now regulations require an auditory warning on both forward and backward zooming.
That's exactly what happened, AO.......uncanny !!! ;)
10:50 sorry for interrupt you again, This sort of amps needs to be played as you do.
This is not a hi-gain amp in any way, so stay away from trying use it like that. It never will you satisfy when trying Halens´ fingertapping.....
This is a surf amp, or twang it, and may use vol. max. and bass max. But vol. at the guitar just a little above initial sound saturation during picking, sounds great! Even with a 10 inch speaker.
Thanks, TC :))
Hi Uncle Doug, I wanna replace the reverb tank, it's an EAV 200 made by Pioneer I guess and it's 8 ohm. I have 1,4 ohm on the input and 140 ohm on the output but no continuity. Which tank could be good for me? Any tank of 8 ohm is ok?
+Pale Pawn A resistance of 1.4 Ohms on the input would correspond to an 8 Ohm impedance, but the 140 Ohms on the output does not match any impedance found in a common tank. Both input and output impedance has to be correct for the tank to work. Refer to this site for details: www.oberlin.edu/staff/thinders/reverb/reverb.html You say you have no continuity, but are able to measure resistance, which is impossible to do without continuity, so I'm not sure the tank is really at fault. Study the site and hopefully it will help you resolve the issue.
Gee I wouldn't know where to begin building one
+357bullfrog You can study YT videos.....or you can simply buy a pedal.
I'd give my eye teeth for a tremelo in mine
+357bullfrog You can always buy or build your own tremolo pedal.
Uncle doug,check out tony campalongo on u-tube.He uses princetons.
I think you mean Jim Campilongo, Glenn. He demo's primarily Telecasters and Princeton Reverbs for the Fender company. His tone is excellent.
Please intonate your guitar ! You take so much effort over your renovation work but your guitar needs some TLC!
You're probably right, SM. I'll check into it.
The guitar has tall frets and I tend to press down too hard, sharping some of the notes, particularly on the G and B strings. Thanks for your input.