Highly Modified 1967 Princeton Reverb Returned to (more) Original Condition

This video features a highly modified 1967 Fender Princeton Reverb that was sent to us for restoration to more original specifications. The procedure provided the opportunity to discuss several topics in detail: 1.) The design and implementation of Pentode/Triode switches 2.) Capacitor Time Constants and their effect upon tremolo speed (very basic discussion with analogy). 3.) DPDT switch theory 4.) Tremolo Footswitches.....does your Fender amp need one, and why? 5.) What is the purpose of Screen Resistors? In addition, we will open some birthday gifts from generous viewers and you will meet Mitzi, the latest addition to our feral cat menagerie.
If you enjoyed the video and would like to help support our channel, please consider making a PayPal contribution to: [e-mail] or becoming a Patreon patron at: / uncledougsvintageamps
NOTES: I apologize for the brief autofocus failure during a portion of the screen resistor presentation. I realize that 1967 was not "Pre-CBS" but the circuit design did predate their takeover.

[@UncleDoug]

NOTE: It should be mentioned that Screen Resistors may well serve additional purposes to those I describe in the video: 1.) Lowering of screen voltage and current if DC resistance of filter choke is not adequate to do so. 2.) Prevention of oscillation (like signal grid blocker).

[@Projacked1]

Those translucent tubes are PTFE I believe. They do it for it's low dielectric value in audiophile-land, for tone improvement.

[@michaelmoore7975]

For the hideous holes hell hath heaved hardship heavily hung.... how 'bout a Pop-Rivet? Those are my go-to hide-a-holes. They make it look like _something_ was intended to go there. Instead of inducing fainting and a case of the vapors, people will look and go "Hmmmm...something _must_ go there...possibly for a different application." But...I've been wrong before. I'm not afraid to admit it, either. It was that time I thought I was wrong about something.... but turned out I was wrong.

[@UncleDoug]

@@michaelmoore7975 Thanks for the helpful suggestion, Michael. I ended up filling the holes with solder, flush with the chassis surface.

[@michaelmoore7975]

@@UncleDoug Even better....no-see-um Kemosabe. The name is Moore....Clayton Moore. A real pro makes it _look_ like he hasn't done anything at all.

[@UncleDoug]

@@michaelmoore7975 Jay Silverheels at your service :)

[@brotherspock8180]

Uncle Doug, you're such a national treasure, and I hereby induct you into the Tube Amp Hall of Fame.

[@UncleDoug]

Wow.....high praise indeed. I gratefully accept and hope that you live long and prosper.

[@demagmusic]

@@UncleDoug I second the nomination

[@UncleDoug]

@@demagmusic Thanks, D :)

[@KeritechElectronics]

@@demagmusic indeed, so would I if I were any authority.

[@vintagetubeamplifiers]

Uncle Doug must be protected at all costs.

[@dkovorik409]

Uncle Doug is back!! Your voice is the cure for depression, man! I can't even understand the meanings of the words. You are a man of wonderful character. Just wanted to thank you! -THANKS!-

[@UncleDoug]

Thanks so much, DK. Glad to be back :)

[@elmadouf]

Hi Uncle Doug, This comment is irrelevant to the video (althought I am currently building a Princeton Reverb). I just wanted to thank you for everything you did on this channel. I started watching your videos in 2013 I think, when I first got interested in tube amps. You gave me the knowledge and confidence to try and start building my first amplifier. Armed with that confidence I went and got interested in guitar building as well and started my first electric guitar with a few tools in my garage. This led me to studying lutherie, to apprentice with a luthier, to fly to Canada to get a 3-year intensive education at the National School of lutherie in Québec. I am now a diplomed and experienced luthier and business owner, and in a way, you participated to all that without knowing it. I am very grateful and I needed you to know it. Cheers from France.

[@UncleDoug]

It's wonderful to hear of your successful career development, Francois. We are proud to have played a (relatively minor) role in your achievement and wish you the very best in all your pursuits.

[@brianboyd2957]

Uncle Doug, if you were an employee at Fender back in the day, I am pretty sure that you'd be Leo's right hand. Knowing the trade and applying it in a neat workmanlike fashion is essential for excellence. Being able to convey said methods and knowledge with clarity is an entirely whole new level. Thank you for sharing your gift, professor.

[@UncleDoug]

Wow, thanks so much, Brian. High praise indeed :)

[@archangr]

Uncle Doug, you're a true living legend. Your videos helped me to successfully repair my VOX AC-15 amp and also inspired me to build my own Princeton Reverb from the scratch!!!!

[@UncleDoug]

That is really great to hear, Arturo. Congratulations on your success and best wishes for its continuation.

[@kengevers8738]

Thanks for sharing your knowledge. I think this is your best video to date. A full explanation of the triode/pentode sw, chokes, and screen resistors in all related components in an amplifier. Your explanations make the most sense to me. Thank you. 😊

[@UncleDoug]

Thanks so much, Ken. Glad to hear it :)

[@edwardebel1847]

Ah…breakfast and Unca Doug…could life be better? The answer is none…none more better! Another magnificent chapter. Thanks again!

[@UncleDoug]

You're welcome, Ed. Glad you enjoyed it :)

[@tonymanns8249]

Thanks Doug for being an animal lover. I rescued my 15-year-old cat two years ago.

[@UncleDoug]

We love the furry little fellows and they bring us great happiness.

[@GuitarSmith.]

Got home our usual Sunday grocery shopping, sat down with a cup of coffee at the PC and low & behold a new Uncle Doug video. I guess my shop work can wait for a little while.

[@UncleDoug]

I hope it's enjoyable, Martin :)

[@GuitarSmith.]

@@UncleDoug Very instructive and good entertainment at the same time. Thanks Doug. Happy Birthday, Beer is on me.

[@UncleDoug]

@@GuitarSmith. Sounds good, Martin. Where can Jack and I meet you ?

[@GuitarSmith.]

@@UncleDoug When Simon and I get down to Texas I owe you one. I'd bring Riley too but he's not a beer guy, doesn't even like cat treats.

[@UncleDoug]

@@GuitarSmith. We have some boutique catnip for Riley ;)

[@joelwilliams6440]

We are not worthy,You are the Jedi Master. Never stop, This information and knowledge can never be lost!

[@UncleDoug]

Thanks so much, Joel. We're entering the fourth quarter (of a century), but still have a few good plays to run :)

[@golgothaassassin5035]

I've been watching and learning for some time now. Thank You for taking the time to teach us. The thing that most touches me is your kindness for the kitties. My daughter and I foster a lot of neglected or abused kitties ourselves, and teach them to trust and love again. Our animal shelters are over ran with forgotten pets. It is a great thing that you do to help out, small gestures can make huge differences. Your are truly a Gentleman and Scholar

[@UncleDoug]

Thanks so much, GA. It's a shame that many people are so callous regarding pets. The animals can provide endless loyalty......too bad the humans are unwilling to do so :( Keep up the good work.

[@Ireland831]

...."until the high voltage winding is fried...as well as your pocket book". UD you have a great sense of humor. Your vids are so educational and thanks for your content. I learn new things everytime I watch your vids.

[@UncleDoug]

Glad you enjoyed the video, I831

[@tomw9875]

Great video Uncle Doug. Those viewing your videos appreciate your vocal delivery, neat penmanship, and simple hand drawn wiring diagrams. We can tell you take the effort to these details as perfect as you are able to. Getting these little details right makes transferring your knowledge to the viewers as easy/simple as possible. THANK YOU Uncle Doug!

[@UncleDoug]

You're quite welcome, Tom. So glad you enjoyed it.

[@jakeharris2044]

Was that a new jam I heard?! You carry on my wayward uncle. I love it.

[@UncleDoug]

Will do, Jake. Glad you liked it :)

[@brianm9282]

Everyone's favorite Uncle is back!

[@UncleDoug]

Thanks, Brian :)

[@mrgrinch14]

Always love your videos Uncle Doug. You've inspired me to to (VERY CAREFULLY) make the jump from just making pedals to amps and it's been a ton of fun!

[@UncleDoug]

That's great news, PP. Best of luck with all your projects.

[@KarlKarsnark]

Good luck! Gonna have to change that screen name soon ;)

[@snowhyt77]

Greetings UD. Thanks for another episode in the never ending masterclass! I don't mind the digressions, they're what makes you so enjoyable. I learn something from you with every video. Great Job.

[@UncleDoug]

Thanks, SW. Repair videos get a little redundant after a while, so some digressions tend to break up the momentum.

[@tonymanns8249]

Very good Doug. I'm an electronic tech and am well versed in tube amps, but I have learned from this video about screen resistors. Thanks.

[@UncleDoug]

That's great to hear, Tony.

[@stevenmoffitt1643]

Any extra information you include, even if it is something you've covered is always appreciated.

[@UncleDoug]

Thanks for the input, Steven.

[@niklet805]

The digressions are the reason I watch your channel. You inform us with your explanations, for example the spring/capacitor analogy was very useful. Thanks.

[@UncleDoug]

Thanks, Nik. Glad you like them :)

[@Tom_Emody]

I don’t have the foggiest idea what you are talking about….but I sure do love your videos anyway. Seriously speaking….I have learned some new things while enjoying your vids.

[@UncleDoug]

That's great to hear, Tom. Keep watching and it will eventually make good sense.

[@daveogarf]

LOVES 'DEM KITTEHZ, Uncle DOUG! And HAPPY BELATED BIRTHDAY! You truly are a national treasure.

[@UncleDoug]

Thanks so much, Dave :)

[@brianbrophy605]

Uncle Doug, Thank you so much for this very interesting video. I am a first timer and never had any electronic knowledge. This really peaked my interest. I really appreciate your very deliberate and clear delivery.

[@UncleDoug]

You're quite welcome. Brian. Thanks for your nice comments :)

[@SDS-ff8ed]

I think you have taught more about Tube amps than any formal education could hope to accomplish. Thanks for making these videos!

[@UncleDoug]

That's great news, SDS. Glad to hear it :)

[@jaguarracingus]

hi uncle doug. back in country and now in the new digs in the woods. this was a good vid to sit and watch whilst sucking down the morning caffeine fix. thanks for providing some continuity in life. say hi to the furifriends for me. =dok=

[@UncleDoug]

Greetings, Jag, and welcome back. Will do :)

[@tonymanns8249]

Doug your spring analogy to capacitance was brilliant.

[@UncleDoug]

Thanks, Tony :)

[@richreid7098]

Right at 59 minutes you reminded me of a great story. Many years ago in a life far away. I had a math test. The teacher said to read the printed instructions and follow them. The instructions said first to print your name in the upper right corner. Second, read all directions before starting the test. I don't remember the instructions in between but the last one said, leave all the answers blank, you have finished. Turn in your test and you may leave the room. I read through 2 more times to be sure I read it correctly. I then got up put my test sheet on his desk and left. I was the first one to leave. True story.

[@UncleDoug]

I had a similar experience in a high school math class......and fell for it, spending lots of time answering every question and request, including "stand up in class and say I am a smart guy who follows instructions". Boy was I embarrassed.

[@timothygrupp]

Love the digressions...that's how I learn stuff (never too old for that!) Thanks!

[@UncleDoug]

Glad to hear it, Tim. Thanks :)

[@pauldavis6356]

Good to hear from you again. I hope all is well !

[@UncleDoug]

Never better, Paul. You too, I hope.

[@waynecook5836]

I'm glad to be back in class,I spent my birthday 4/28 with some lovely nurses

[@UncleDoug]

Welcome back, Wayne. I'll bet you miss those sponge baths :)

[@jonnybeck6723]

I came back and enjoyed my lesson. I always assume that everything affects tone (ah ha) Thanx so much teach ...and God Bless you as well

[@UncleDoug]

Thanks, Jonny. Likewise :)

[@marknielsen8977]

The addition learning features you included are what make your channel priceless. You've mentioned before your teaching background and boy I bet you would have been the best teacher ever, 100% clear and concise. It's with great gratitude you continue to be so here on the interweb for all to enjoy. Thanks Uncle Doug.

[@UncleDoug]

Thanks for all the very nice comments, Mark.

[@eduardoOlima]

Always a master class even tô someone with superficial knoledges like me. I dont dare building a tube amp.but watch alll vídeos I can. Thank tou Mr Doug

[@UncleDoug]

You're welcome, Ed. Be sure you learn all the safety rules first :)

[@eduardoOlima]

@@UncleDoug thats my major concerns.... 400v or 600v scare me to desth lol

[@UncleDoug]

@@eduardoOlima It should, Ed. That' why safety is so important.

[@MrMeik1970]

Nice that you have such a big heart for animals. This makes this channel even more valuable. You are the best teacher Uncle Doug 😉

[@UncleDoug]

Thanks so much, Meik :)

[@plgplgplg]

More gold! Great taste in get yer ya yas and Kansas Petty demo tunes. Those cats can play! The Carling switch out and extra holes expose your purist tendencies, all part of the charm. Good job on the kitty rescue too.

[@UncleDoug]

Thanks thrice, P3 :)

[@jaytee8188]

Oh here we go… a video from Amp and The Hot Rod Master. My weekend is complete, Thanks UD. 👍

[@UncleDoug]

We hope you enjoy it, JT :)

[@jaytee8188]

@@UncleDoug Thanks UD and for sure I will, several times Really envious of the Hot Rod stuff, not much like it over here in England. In fact I didn’t see much like it when I lived over in NJ quite a few years (decades) ago!

[@UncleDoug]

@@jaytee8188 Sounds good, JT. I know that Eric Clapton and Jeff Beck are major hot rod enthusiasts. Obviously they have good taste in music AND cars ;)

[@jaytee8188]

@@UncleDoug Absolutely UD, spot on.

[@lrdisco2005]

We are both still alive. Result. Great video as always.

[@UncleDoug]

Yep :) Thanks, LR.

[@lifegettingintheway2710]

At 53:59 your aha! moment shown a light. I have a customer's amp on the bench and earlier today the new TAD 6v6 matched pair arrived. One of the tubes that came with the amp failed in a spectacular way in my tube tester, possibly an omen of the pending nova hovering in the current night sky. With the new tubes in they both had 36mA with -27v bias voltage. Nice match, though. Taking a break I stumbled onto this thread over a sandwich and at 53:62 I went back to the shop and saw a 100k resistor in that very spot. I quickly removed it and saw a perfect 22mA on both tubes. It must have been a common mod in the day as I don't believe much in coincidences. And that is probably why the original tubes were in such bad shape. Thanks for the lead on that!

[@UncleDoug]

You're welcome. I'm glad the video was helpful.

[@rgbplumbinghilton]

This is a long awaited video. Great to be sat here in my van, Sandwiches and strong tea for lunch and an Uncle Doug amp vid.

[@UncleDoug]

We hope you enjoyed it, Richard :)

[@rgbplumbinghilton]

@@UncleDoug I always enjoy your videos. Especially on a Monday to ease away those Monday blues 🙂

[@bertrodriguez3087]

Doug playing Kansas!!?? I almost fell off my chair lol!! Sorry I've been away, but I'm slammed (I know you know what that is like). I don't know what to say about this video. I believe it's one of your best (and there are many that are your best). All the clear and precise explanations of the "WHY", is the reason I was attracted to your channel many years ago now. I've said it before, and I'll say it again, the world needs more teachers like you. Period!! You are a rare commodity in this day and age my friend. God Bless you!!

[@UncleDoug]

Wow....thanks so much for your very nice comments, Bert. We really appreciate them, and Ollie & Jack promise to learn some new tunes just for you :)

[@hijmestoffels5171]

Thank you for this video. I do appreciate the digressions. Watching this restoration makes me realize how happy I am to never have modified the Princeton non-reverb that I bought in 1977. It is still working great. Only my cat has done some modifications on the grill cloth.

[@UncleDoug]

Glad it was helpful, Hijme. I really have to watch my cats to prevent the shredding of the grill cloth.

[@davidsimpson3380]

I believe Uncle Doug attains perfection by correcting all of the imperfections, even the little ones that the pros are too busy to deal with. You take it from craft to art! Thank-you :)

[@UncleDoug]

Wow.....thanks so much, David.

[@davidsimpson3380]

@@UncleDoug It's true :) Thank-you for sharing Uncle Doug.

[@davidsimpson3380]

@@UncleDoug I have a question/idea for you. I have a princeton and a champ and really love how they stack and sound together. I run the champ clean and the princeton wet and the tone is wonderful but I don't like taking two amps to a get-together. I'm thinking of taking a deluxe reverb chassis and building a princeton on one side and a champ on the other with each circuit having independant speakers and output transformers. Do you think I could build this arrangement with a single beefy power transformer like a stereo audio amp?

[@UncleDoug]

@@davidsimpson3380 Rather than two complete and separate amp circuits in one cabinet.....complex and very heavy.....why not a single circuit with a Champ preamp channel and a separate Princeton Reverb channel, then jumper the inputs to combine them?

[@davidsimpson3380]

​@@UncleDoug Thank-you I'll have to experiment with that :) I don't know if what I'm enjoying is the two preamps combined or the layering of push-pull and single ended outputs ...

[@williamexon171]

The digressions were great, all the detail you can provide is most welcome.

[@UncleDoug]

Glad to hear it, William.

[@RJ-bn5uw]

Jack and Ollie AKA The KillTonettes , they are absolutely killin it in all your video's . Hard to find them on vinyl . :o)

[@UncleDoug]

They will be pleased to hear that, RJ. Their Greatest Hits album was just released on Catbox Records, entitled "OJ Strikes Again" ;)

[@jonghj]

I love the midnight Rambler take out!!! Mighty fine tone!

[@UncleDoug]

Thanks, Hank.

[@richreid7098]

So nice to see you again. I always enjoy the opportunity to visit my brilliant uncle!

[@UncleDoug]

Wow....thanks so much, Rich. The feeling is mutual :)

[@w.rustylane5650]

Just love your humor, uncle Doug. Wow, above and beyond is what we called it in the USMC. I'd be proud to own that amp after you worked on it! Sorry, not a cat fan. We've got a nearly 100 lb. golden doodle. Cheers & 73 from W Rusty Lane K9POW in eastern TN

[@UncleDoug]

Thanks, Rusty. We appreciate it :)

[@Andreas_Straub]

Just a minor correction: a capacitor by itself has no time constant. Only a circuit consisting of a capacitor plus for example a resistor or inductor has a time constant. Besides this little error this was again a very useful and instructional video!

[@UncleDoug]

Thanks for your helpful input, Andreas.

[@mp-ov9dh]

another great Uncle Doug video for the library. You have taught me and so many others so much about these things and electronics in general. I would not have near the confidence I have without what has been covered on this channel. I recommend you every time i get a chance!!

[@UncleDoug]

Thanks so much, MP. That's great to hear.

[@TheGuitologist]

Hey Doug. Great to see you! A note on screen resistors. I think the idea of screen resistors being a sacrificial part is a newer one that Fender perhaps did not have in mind. According to some of my reading, screen resistors used to be known as "screen stoppers" just like "grid stoppers". They were used to keep circuits stable and prevent oscillations in the same way grid stoppers are used. They also limit the current going to the screens. There is a discussion of this in the RCA Radiotron Designer Handbook, if you possess a copy. It even suggests the typical value for this resistor in the 500 ohms range, which is undoubtedly where Fender and everyone else got the 470 values. And also, it insists you should ensure the wattage rating is sufficient for the dissipation. In other words, they should not be considered a sacrificial part. Anyway, back to the video! Again, great to see you. Hope all is well.

[@davidklang8174]

Everything you say is correct, but Fender still ignored screen resistors completely until they moved the choke between the screens and center tap/standby switch. This leaves one end of the choke "flapping in the wind," so using the switch makes the choke ring. Loudly. The screen Rs tame it a bit. Fender did the right thing for the wrong reason. Every screen should really have a resistor.

[@mendittoamplification]

@@Bob-Whiting No, he meant 500 ohms.

[@robnic52]

@@Bob-Whiting In Doug's explanation he repeatedly talks about 470 ohm screen resistors. I think The Guitologist's typo was in adding the k, he actually meant 500 ohms. If that was what you were trying to say, please excuse me. :) 👍

[@mendittoamplification]

He meant to write 470 ohms but accidentally wrote 470K ohms. If you use 470K, you will not be very pleased with the results.

[@srtamplification]

I think the screen resistors, much like grid stoppers, were more vital in RF applications. There are a lot of hi-fi amplifiers that do not utilize screen resistors, but come right off of an ultra-linear output transformer instead.

[@wrenchhead944]

You should teach classes on this type of work. Your explanations are the best around . Even an idiot like me can understand what you are explaining .

[@UncleDoug]

I think of our videos as being a free course of instruction in tube electronics, Brian. Thanks :)

[@bevo65]

So I find myself studying for my General Class ham upgrade. It includes tons of electronics. More than once during my studies, I’ve harkened back to the great Uncle Doug. 🤘🤠

[@UncleDoug]

That's great to hear, Bevo. Good luck on your exam.

[@tubeztoonz]

Thanks for another great video, Uncle Doug. Belated Happy Birthday!

[@UncleDoug]

Thanks, TT. Glad you enjoyed it :)

[@m1goodwin]

Without further ado! Ha ha! Best laugh I had all week! Thank you uncle Doug!

[@UncleDoug]

Glad you enjoyed it, MB :)

[@Bob-Whiting]

@Uncle Doug It is good to be back! I survived the massive surgery which was by far, the most complicated and painful of the Ten surgeries. It is good to see you and everyone else once again. This was a good one, well done, and you obviously know your Princetons. She looks and sounds great so you can say you made some fine choices. Thanks.

[@UncleDoug]

Thanks so much, Robert. Glad to hear you're back on your feet and recuperating well.

[@Bob-Whiting]

@@UncleDoug Thanks Uncle D.

[@ronnewby3196]

Happy Birthday! another great video!

[@UncleDoug]

Thank you, Ron :)

[@ronnewby3196]

@@UncleDoug Your welcome.

[@sgt.grinch3299]

@Uncle Doug, my friend HK Guitar recommended your channel to me last night. So, here I am, your newest subscriber. It’s time to learn. Nice to meet you Sir.

[@UncleDoug]

We are honored by your presence, Mr G. Welcome aboard for what I hope is a long and enjoyable ride.

[@irusman62]

I loved the entire video UD I hope little Mizei gets her tummy full and recovers quickly to a proper sized cat. and thank you and your wife for covering her vet bills, it warms my heart to see the love, you both have for all living creatures.

[@UncleDoug]

Thanks, Russell. Mitzi is doing quite well :)

[@A.J.Collins]

Thank you for your great work. Your analogy of springs in relation to capacitors was especially edifying. I appreciate your generosity is sharing your knowledge. God's peace to you and your family.

[@UncleDoug]

Glad you enjoyed it, AJ. Likewise to you and yours.

[@JanLarsenFredriksen]

Every video from my favourit uncle is like , Xmas eve, new year, Birthday party and midsommer all together. Finally a new enjoyable class. Thank you 🙏

[@UncleDoug]

Great to hear it, Jan. The pleasure is mine :)

[@brentstewart59]

Happy belated birthday Uncle Doug. Many thanks for sharing your knowledge with all of us. Sir you just have a way of explaining things that just make it easy to understand what's going on and why.

[@UncleDoug]

Thanks so much, Brent.

[@danielcrook9504]

Uncle Doug, Always a joy to watch your clips and learn from your expertise. A friend came over and looked at my work on this amp I am building and while impressed, he asked a question that I was unsure how to answer correctly. He asked if a tube amp could, or ever has been built from a deep cycle marine 12 volt battery. I told him about your clips and he was only interested in whether it could be done rather than any learning that he might glean from your videos. I answered him that I thought that one of the problems would be how to double the voltage enough times to feed even a 12A?? so that you could supply a speaker with a signal. He was interested in only enough to make a watt or two so that one could virtually play guitar anywhere. I told him there are numerous battery operated amps that make enough power to play for awhile but he was insistent on whether it had ever been done. As always, thanks for indulging crazy questions...Daniel

[@UncleDoug]

I have no idea, Daniel.....sorry to let you down......but your friend could easily do an internet search on the subject.

[@DonnTarris]

Fabulous and informative video, very glad for the diversions into deeper waters on the "pentode-triode" switch, as well as the screen resistors. As I'm in the long process of building the amp I should have bought way back in 1970 (this one), it helps me further understand the entire circuit!! As others have mentioned, truly a masterclass!!

[@UncleDoug]

Wow.....thanks so much for the very nice comments, Donn :)

[@BurnFX1]

You are truly a gold mine, thank you my dear uncle!

[@UncleDoug]

Thanks so much, B :)

[@stratcat4450]

Happy belated birthday uncle Doug. Your digressions, in depth knowledge an teachings keep at a higher level than anyone else on YT. Thank you for what you do.

[@UncleDoug]

Thank you kindly, SM. We really appreciate it :)

[@bluemule3891]

DMiester, another great vid, by the way Utube knocked my notification alert off, and I had to reset it, everyone may want to check theirs. Oh yeah, Kansas, nice, now all you need is some Ritchie B, and you are set. Long Live Leslies The Ever C3 Blue Mule

[@UncleDoug]

Thanks, BM. I'll keep your request in mind for the future.

[@cliffyoung5712]

This video really shows the importance of bias current. just tossing in an NOS pair of tubes would have made for a short tube life along with other issues.

[@UncleDoug]

So true, Cliff. You have to adjust the circuit to suit the new tubes.

[@tomstiel7576]

Awesome content Uncle Doug,you are in my opinion the gold standard of vintage amp repair. I firmly believe there is a special place in heaven for those who look after Gods furry creations warms my heart to see you taking care of those felines,,,,word must have got out on the street,,,,the cat found you... God bless

[@UncleDoug]

Thanks for your very kind words, Tom. The kitties give back every bit of love they receive.....and are always welcome :)

[@codyreynolds6333]

Just found your channel its awsome I just bought my first amp kit a kld 5e3 e from kld its not the exact original and I have no idea what I'm doing but thats not going to stop me just hope it works when I'm done

[@UncleDoug]

Welcome aboard, Cody. Best of luck with your project :)

[@jeffm8122]

I'm sure the owner of the amp will be very pleased with the result of all your attention to detail. Amongst the components in an amp, screen resistors are probably the most overlooked and misunderstood. Credit to you for bringing them to the fore. Screen voltage and the correct way it is obtained, particularly when lower than the plate voltage, is a subject all of its own. I see another lucky kitty is benefiting from your good nature. The way she was tucking into her food she will be fit and healthy in no time. Many happy returns for your birthday, may your current have no ripple and your electrolytics never leak. Stay healthy. Regards, Jeff.

[@UncleDoug]

Thanks so much for all the very nice comments, Jeff. Mitzi sends her regards :)

[@suomi35]

Loved the video, as always. The spring/capacitor extra was really a great illustration too. Cheers!

[@UncleDoug]

Glad you enjoyed it, S :)

[@rickbaker4571]

What a beaut... the info, the rebuild, the sound. Dang, you just crushed that one... HBD, as well!!! To many many many more!! Thanks for bringing us along.

[@UncleDoug]

Thanks so much, Rick :)

[@KeritechElectronics]

And a joy for ever.

[@djentlover]

Glad you're back Mr. Doug :)

[@UncleDoug]

Me too, DJ. At my age, it's good to be anywhere above ground ;)

[@garryparker337]

Thanks Uncle Doug for your expertise in solving the mysteries and explaining the workings of these wonderful amps. Timely also as I've been anxiously waiting for my replica Princeton Reverb kit to be shipped. Brilliant as always :)

[@UncleDoug]

Glad you enjoyed it, Garry. Best of luck with your project.

[@Silent-Lucidity]

Happy Belated Birthday! Lol! Wonderful video, Uncle Doug! Welcome, Mitzy (spelling??)!!!

[@UncleDoug]

Thanks so much, S-L :)

[@Wade6242]

Hi Doug, thanks for sharing

[@UncleDoug]

I hope you enjoyed it, Wade :)

[@SidLives]

I could listen to Uncle Doug all day, just a soothing voice mixed with wit, love it (was hoping for some Hot Rod interlude as well, maybe next time)

[@UncleDoug]

Thanks so much, Paul :) I'll keep your request in mind.

[@wrenchhead6840]

Another awesome video…. When i started watching your videos I understood about 10% of what you were talking about…. Two years (and all your amp vids) later, I understand about 45%.

[@UncleDoug]

Thanks !! Stick with it, WH....you're making good progress :)

[@reggiewallace260]

Great video as always. Thank you for you effort in producing this one.

[@UncleDoug]

Glad you enjoyed it, Reggie :)

[@deplinenoise]

Don’t know if you’ve done a segment on optoisolators in amp and audio circuits, but could otherwise be a great idea for a rainy day video. As always, extremely helpful and enjoyable video.

[@UncleDoug]

I have done several videos on the different types of tremolo, Andreas. Check my video list.

[@MrMarkar1959]

👍🏼If i only knew what You forgot the old '71 Fender TFL5005D in the closet would live again🎸

[@UncleDoug]

Get it out and give it a try, MR.....but be careful.

[@billklement2492]

Doug, really nice job! Congrats on the new kitty! She looks cute! And thumbs up for getting her fixed. My wife caught all of the 10 cats in the colony she takes care of and had them fixed. They're all outdoor cats, though a couple come in to hang out. But they don't stay long. If the dog is sleeping, one will go upstairs and watch her sleep. It's really funny! Thanks for the video!

[@UncleDoug]

Thanks so much, Bill. Bless you and your wife for your kindness to our furry pals.

[@DoctorCalabria]

Thanks Unca’ Doug. Once again you knocked it out of the park. I guess you get better with age because I think this video had a little bit of everything fender.

[@UncleDoug]

Thanks, Frank. I'm glad you enjoyed the video :)

[@aaspookyaa]

Hi Doug I hope you're well, you sound really good here

[@UncleDoug]

Never better, AA. Thanks !!!

[@paulsto6516]

Good show, Uncle Doug. Good show!

[@UncleDoug]

Thanks, PS :)

[@jasonperez7811]

I've learned a lot from your channel. Thanks for doing this. I got a pristine untouched guild thunderstar lead with all original components and tunes. The owner sold it for 50 bucks because it smoked the last time he used it. Because of your channel I was able to determine that the power tubes just needed to be biased correctly and it works amazingly.

[@UncleDoug]

That's great news, Jason. Always glad to hear that the videos have been helpful.

[@zyadnob5449]

great job uncle Doug...beautiful

[@UncleDoug]

Thanks, Z :)

[@squiertelecaster6854]

I love it when you go to your private stash, RCA 6V6 tubes, switches, sockets...I have a 66 and a 67 PR, I bet it smelled great too.

[@UncleDoug]

My Al Capone's Vault of tubes, etc. has never let me down. Even Geraldo found something good in it.

[@garryormson4609]

Just purchased a 65 Princeton (OC) wish i could somehow contact you… videos and the humour are fabulous! Thanks for what you do

[@UncleDoug]

Glad you enjoy the videos, Garry. You can message me on my FB page: Uncle Doug's Vintage Amps.

[@danjohnson4819]

A little late but Happy 75th Birthday. To good health and many more 🍻

[@UncleDoug]

Thanks, Dan :)

[@davidshutt2273]

Thanks again for your informative info, uncle d

[@UncleDoug]

You're welcome, David.

[@georyans]

Great video for people building there own amps cathode biasing at 90% and additional two pot grid bias to match at 70% works for me ps you are a national treasure

[@UncleDoug]

Thanks so much, G :)

[@Roblinsell]

uncle Doug you are a dead set craftsman... thanks for remembering us down under!!!...:) you make me wish I studied electronic better during my early years

[@UncleDoug]

Thanks so much, Robert :) Australia is on my list of must-sees while I still can :)

[@nicko6710]

one of the best amps

[@UncleDoug]

Yes, indeed :)

[@christophergallagher531]

hey , I have learned a lot from you, thankyou. Recently I came up with a new trick, you may already know and use. Caig Deoxit belongs on the shelf, I have D5 now. Applying the stuff has always been hit or miss for me. A little in the right place does it. There used to be put ups other than the shot gun spray can. I started putting some a bottle cap and dipping a tooth pick. Here is the new twist. An old fountain pen, or just a nib. Control and no constant dipping! Thanks for your content. Chris

[@UncleDoug]

Thanks for sharing this tip, Chris :)

[@goodun2974]

I use a syringe to apply control cleaner.

[@christophergallagher531]

@@goodun2974 Good idea! I have some that can be capped off. I sure waste a lot getting it out of the can. One of those drats. Chris

[@goodun2974]

@@christophergallagher531 , unfortunately, some control cleaners will cause the rubber seal or gasket of the syringe to swell, so you might not be able to leave the cleaning chemicals in the syringe. I'm still trying to find a source for solvent-safe syringes, but sometimes you can replace the syringe gasket with a chemical resistant nitrile or silicone O-ring.

[@chriswareham]

The digressions were great, and a belated happy birthday Uncle D. Delighted to see Mitzi join your extended family too.

[@UncleDoug]

Glad to hear it, Chris. Thanks so much :)

[@Antony_Jenner]

Hey Doug Australia here. I have a great restore to do, I bought a all original 1975 Super Twin that needs some tender loving care. Even monsters need love. Hope you are well, stay safe.

[@UncleDoug]

We are indeed, AL. You too, I hope. Good luck with the project.

[@skip1835]

The results speak for themselves - - probably sounds better now than it did back in those 60's - like you UD, I was around back then, playing drums in my HS band, we had a couple of Fenders, at least one Silvertone and I don't recall what the bass player was using for an amp - - - I sure enjoyed this video especially the sound demo, imho, you're right UD, you've got the tremolo dead nuts perfect - - hmm, seems like I missed the original party, maybe I missed the notice or it didn't show up - - no matter - - thanks UD!

[@UncleDoug]

Thanks so much for all the very nice comments, Skip.

[@TheBuzzCatt]

Uncle Doug, These are my favorite cat videos'.

[@UncleDoug]

That's great to hear, Art :)