'69 Princeton Reverb.....Badly Burned, Brutally Botched, and (finally) Reborn

Sdílet
Vložit
  • čas přidán 4. 03. 2019
  • This video records the challenging restoration of a 1969 Fender Princeton Reverb which was badly burned in a fire. The chassis was rescued by the owner, who hand-built a beautiful, original-looking replacement cabinet with a nice Jensen speaker and new Accutronics reverb tank......then, very sadly, it was turned over to a local "technician" who proceeded to mis-wire it badly, with several short circuits, missing wires and connections, and improper component values, creating a dysfunctional nightmare.
    In desperation, it was sent to me for repair.....and presented one of the biggest repair challenges I have ever faced. This video follows the step-by-step elimination of (hopefully) all the previous mistakes, resulting in one of the best sounding PR's I have ever heard. I hope you agree :)
    In response to viewer requests, I have focused on relating schematics to actual circuits, given detailed explanations of why certain repairs work, and thoroughly discussed pertinent tube amp circuitry details......all in an attempt to maximize the educational content of this video.
    If you enjoy advertising-free videos like this, please subscribe to my channel and consider becoming a Patreon patron at: / uncledougsvintageamps or making a PayPal contribution to dldcam@aol.com. Also if you have any vintage tube amps or gear that you would like to contribute as possible video features, please provide your e-mail address and I will contact you.
    Thanks so much !!!
  • Hudba

Komentáře • 1,2K

  • @UncleDoug
    @UncleDoug  Před 5 lety +167

    NOTES: 1.) I have upgraded to a broadband Internet provider, with uploads that are now 10X faster. I believe this has resulted in improved audio and video. See what you think. 2.) I did not realize during video production that the owner actually hand-built the replica cabinet, using vintage Fender Tolex. It completely fooled me. I thought it was an original replacement.

    • @gerthalberg9735
      @gerthalberg9735 Před 5 lety +9

      Hi Uncle - right on regarding video & audio

    • @freepress8451
      @freepress8451 Před 5 lety +4

      Another fine video - do you celebrate Pancake Day (Shrove Tuesday) in US?

    • @UncleDoug
      @UncleDoug  Před 5 lety +20

      Thanks guys. No, we only celebrate Catnip Day......every day :)

    • @peterespada6226
      @peterespada6226 Před 5 lety +2

      I just discovered your videos a couple months

    • @peterespada6226
      @peterespada6226 Před 5 lety +3

      ago and am amazed with your deep erudition regarding electronics. Were you once a college professor or teacher in this field? I’ve learned so much so easily that I had always wondered about watching your videos...

  • @Bbendfender
    @Bbendfender Před 5 lety +24

    Hey guys, I am the owner of this little Princeton Reverb. I just had to save it when I saw it. I'm not a tech so I let a "friend" look at it. He tried but couldn't do the job correctly. Along with this Princeton Reverb I also got a '63 Fender Bandmaster that was in the same burned condition of the Princeton. When I can afford it, I may get it refurbished. I know it will be another great amp. I am thankful to Uncle Doug for his great work.

    • @UncleDoug
      @UncleDoug  Před 5 lety +9

      Thanks for your comments, Bob. I hope you enjoyed the video. The PR is now one of the best sounding ones I have ever heard. We can talk about the Bandmaster. Hopefully, it hasn't been worked on previously. Also, the replica cabinet you constructed is truly outstanding. You have done us all a great favor by saving this badly damaged PR from the landfill.

  • @edwardebel1847
    @edwardebel1847 Před 11 dny

    Your channel is the "Watch Mr. Wizard" for us aging children. So much education "disguised" as entertainment...or is it the other way around? I wish my electronic technology classes had been this engaging. Again, THANKS! 😊

    • @UncleDoug
      @UncleDoug  Před 11 dny

      High praise indeed, Edward. Thanks !!

  • @coronadofishingclub3478
    @coronadofishingclub3478 Před 5 lety +72

    Warm regards Uncle Doug. I enter into chemo therapy for lymphoma tomorrow and I hope to see some more videos to help me pass the time in the hospital. I wish your videos had been available 20 years ago when I started teaching myself about tube electronics, I could’ve avoided many mistakes. Thank you so much for taking the time to clarify and demystify this stuff! Once I beat the cancer I’m gonna start a new amp build and I owe it to you for re kindling my fascination for this wacky stuff. Cheers, Tim.

    • @UncleDoug
      @UncleDoug  Před 5 lety +24

      We are all wishing you the very best for a successful treatment and full recovery, Tim. The world needs all the tube amp lovers it can get. Your presence is definitely required.....so get well quick !!!

    • @willford8475
      @willford8475 Před 5 lety +3

      Good Luck, Mate. 👍

    • @lousekoya1803
      @lousekoya1803 Před 5 lety +1

      We wanna see you back here in shape soon !!........Regards!...........Lou from Canada !!

    • @FishnMusician
      @FishnMusician Před 5 lety +1

      Tim, get well soon man. You have folks pulling for you, whether you know it or not. Hoping for the best! Take care, and the very best of luck to you and yours.

    • @tatialo37
      @tatialo37 Před 4 lety +1

      Praying for you!!!

  • @vhollund
    @vhollund Před 4 lety +16

    I love watching this pretending i understand more than half of what's going on
    Maybe if i watch enough I'll learn it

    • @soulvaccination8679
      @soulvaccination8679 Před 3 lety +1

      Thats what i do...Ijust keep watching it and watching it and all of a sudden i get a moment of clarity .

    • @Dennis-mq6or
      @Dennis-mq6or Před 2 lety

      @@soulvaccination8679 Same here!

  • @izzysantiago978
    @izzysantiago978 Před 5 lety +120

    The 2 thumbs down are the 2 idiots that messed up the wiring on this amp.

    • @UncleDoug
      @UncleDoug  Před 5 lety +50

      .......and their reward will be a colonoscopy with the unbiased 6V6 that blistered my finger :)

    • @HasteFrankie
      @HasteFrankie Před 5 lety +6

      @@UncleDoug ha! they deserve it. Hope that heals up quick. thank you for the great content as always!

    • @freepress8451
      @freepress8451 Před 5 lety +2

      @@UncleDoug Ouch

    • @jagtone
      @jagtone Před 5 lety +2

      LOL!

    • @WCM1945
      @WCM1945 Před 5 lety +4

      @@UncleDoug _However..._ You _did_ notice the cherry-red plates, didn't you? Shouldn't that have given you a clue as to the temp of the tubes?
      I share you dissatisfaction with the "tech" who did the original work... He either didn't check his work for function, or just didn't give a s**t. I made some wiring errors in my time, but I would **_*never_* have let an amp in that condition leave my workbench.

  • @deadfreightwest5956
    @deadfreightwest5956 Před 5 lety +40

    _"With the axe in one hand, and the guitar in the other... which sounds redundant..."_ - I burst out laughing at that one. I don't even play guitar, but I got it.

    • @UncleDoug
      @UncleDoug  Před 5 lety +3

      Thanks, DF. Fortunately, I didn't get mixed up and play the axe while chopping with the guitar :)

    • @ronniecastellanos8223
      @ronniecastellanos8223 Před 4 lety

      @@UncleDoug Uncle doug I need app doctor I've been using amp for music on my phone during family functions and she started to smell smoky what do I do help Uncle duggy

    • @JalopyTechnology
      @JalopyTechnology Před 4 měsíci

      I saw Uncle Doug at the ER the same day he had his finger repaired. In my case it was an index finger nail was charred by a 6v6... We both sat in the corner wearing dunce caps.

  • @justinbouchard
    @justinbouchard Před 5 lety +22

    The alliteration in the title is fantastically fundamental for fixing fender flubs.

    • @UncleDoug
      @UncleDoug  Před 5 lety +5

      It sums up some serious shortcomings in the circuit :)

    • @jagtone
      @jagtone Před 5 lety +1

      @@UncleDoug -- serious circuit silliness.

    • @UncleDoug
      @UncleDoug  Před 5 lety +2

      Amen, Ben :)

    • @iskandertime747
      @iskandertime747 Před 5 lety

      Well done sir, well done.

    • @goodun6081
      @goodun6081 Před 5 lety +5

      @@UncleDoug , Snappy soldering, savvy skills, scientific study, and steely resolve surely solve somebody else's stupid snafus.

  • @TheGuitologist
    @TheGuitologist Před 5 lety +24

    100% agreed on tube mismatching.

    • @UncleDoug
      @UncleDoug  Před 5 lety +5

      Thanks, Brad :)

    • @fiddlix
      @fiddlix Před 4 lety

      The Guitologist I could not agree more.

    • @Dennis-mq6or
      @Dennis-mq6or Před 2 lety

      Matched tubes might have eliminated that very small bit hum that was left in the amp because the hum would have been cancelled in the output transformer
      The only way to know for sure is to ground the input to the phase inverter.
      One other possible solution would have been to add a 100 ohm potentiometer between the two 100 ohm 'phantom ground' resistors with it's wiper attached to ground. Then adjusting that pot might be able to 'null out' the remaining hum.

  • @rogerraven6976
    @rogerraven6976 Před 4 lety +5

    Thank you for explaining the importance of the beaver dam in reverb setup.

  • @dwightbehm4747
    @dwightbehm4747 Před 3 lety

    Uncle Doug saved the
    Day again
    With very logical
    Repairs to a nice old circuit fender design
    With corrections to the mistakes in parts and wiring. Hope I I'm not
    Annoying but I was up late could not sleep so I watched this vid again entertaining and informative exceptional way of teaching. I certainly
    Like it. Good luck live long

    • @UncleDoug
      @UncleDoug  Před 3 lety

      Viewers saying nice things are never annoying, Dwight. Thanks so much.

  • @NickRatnieks
    @NickRatnieks Před 4 lety

    Woodman spare that amp! Another detective story of impeccable perspicacity. As it is often said: "You can't buy experience."

    • @UncleDoug
      @UncleDoug  Před 4 lety

      Thanks, Nick. Be sure to watch my latest video on the Gibson ga55v cabinet :)

  • @johntempleton6368
    @johntempleton6368 Před 5 lety +19

    You're spot on about the matching of the output tubes. A small to moderate difference in idle current does provide more harmonic content. I've found that once the difference goes beyond the 5 - 8 ma range that a bit of hum creeps in because the common mode rejection of noise is reduced. Great tip. Your trem mods are another killer tip that I've happily borrowed and used. Love your videos.

    • @UncleDoug
      @UncleDoug  Před 5 lety +3

      Thanks so much, John. Yes, excessive mismatch can result in reduced hum cancellation and core saturation......so it must be kept within reasonable limits.

    • @fiddlix
      @fiddlix Před 5 lety +2

      I have been doing this as well for years. We are talking about making music. Not reproducing it...!!

    • @hallanvaara6106
      @hallanvaara6106 Před 4 lety

      I haven't tried mismatched output tubes but Doug's theory about them makes perfect sense to me.

    • @Geopholus
      @Geopholus Před 6 měsíci

      This is a well known effect in electronic music (pulse width variation) if the upper going, wave is related to the bottom going wave by 3/4 or 4/3 it adds some pleasing even harmonics, though I'd rather be in control. of that by my playing style, picking closer the the bridge or the neck.

  • @paulcargo4233
    @paulcargo4233 Před 5 lety +35

    Lets review today's lesson: Electricity like most people will take the path of least resistance.

    • @UncleDoug
      @UncleDoug  Před 5 lety +4

      So it seems, Paul :)

    • @guitarocd9984
      @guitarocd9984 Před 5 lety +4

      My father was a ham radio operator. He built his own radios. I came home one day he was sitting in his chair with a spaced-out look on his face. He grabbed the wrong thing. Electricity went through his hand and blew a 2 inch hole in his leg. The doctor said it could have went to his member. LOL

    • @UncleDoug
      @UncleDoug  Před 5 lety +5

      Thank God he wasn't sitting on a metal stool, GO.

    • @guitarocd9984
      @guitarocd9984 Před 5 lety +4

      The only thing that happened from it was he was mellow for a couple weeks.

    • @UncleDoug
      @UncleDoug  Před 5 lety +4

      @@guitarocd9984 I guess a shock once in a while is good for the soul :)

  • @gitargris
    @gitargris Před 5 lety +13

    Wow! The audio is 100x better! Thanks! Now we can really bask in the sounds of all your great old amps!

    • @UncleDoug
      @UncleDoug  Před 5 lety +6

      Thanks, OR. I changed to a broadband Internet provider (120Mb/sec) and now the videos take 20 minutes to upload instead of 4 hours. I think the slow upload was degrading them.

  • @smasica
    @smasica Před 5 lety +1

    I'm reluctant to slag anyone else's work, but that amp tech must have worked on the amp after a rough night at the club. Wow, rookie mistakes galore.
    Doug, I respect your methodical, meticulous craftsmanship. I learn a bunch with every new video.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      I agree, TM. In this case the previous work is condemnation enough :) Thanks !!!

  • @sting1111
    @sting1111 Před 4 lety +3

    Botched and baked, a classic!

  • @cawfeedawg
    @cawfeedawg Před 5 lety +5

    Doug you have super powers with bringing these beauties back to life.. we don't however want to see you in a cape and tights. 🤣

    • @UncleDoug
      @UncleDoug  Před 5 lety +4

      Thanks. No you don't, CD. In fact several of the neighbors have restraining orders against my donning such attire :)

  • @williamproctor4925
    @williamproctor4925 Před 3 lety

    I very much enjoyed the video on the restoration of a 1969 Fender Princeton Reverb which was badly burned in a fire. I have been experimenting with a tube amp for a while now. Your insights on the workings of the tube amp are in greater detail than the information I received for ITT. Thank you for you video.

    • @UncleDoug
      @UncleDoug  Před 3 lety

      You're welcome, William. Glad you liked it :)

  • @nelsonmedley4349
    @nelsonmedley4349 Před 5 lety

    Nice to listen and see a true master of vintage tubes. You inspire me and I learn lots with your teaching and presentations. You are realy objective and focus about electrónica thank you for teaching us. Congratulations and a big hug.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks so much, Nelson. Likewise :)

  • @midnightraiin4035
    @midnightraiin4035 Před 5 lety +17

    grab your surf board, we've got REvERB:)

    • @UncleDoug
      @UncleDoug  Před 5 lety +3

      Darn right, MR. Time for Jack to "Hang 8".......dew claws don't count.

  • @ObiTrev
    @ObiTrev Před 4 lety +11

    "Do it right or don't do it at all" - Everyone who does it right

  • @MrUbiquitousTech
    @MrUbiquitousTech Před 5 lety

    When I first got into tube radio repair I bought this sad sack of a radio off of ebay. It did not work, nothing happened when you turned it on. I did the shot-gun recapping that newbies are told to do, check the tubes, power switch, etc. Got the schematic, scratched my head over it for a while before I realized (newbie recall) that someone in the past had removed the canned-ohm resistor from the radio, wired the radio with it out of circuit and no replacement resistors! Then to add insult to injury they ran both side of the line cord to one tube. So hot and common through the switch and then to different pins on the rectifier. And no power going anywhere else...... And it all looked like old work so it happened a long time ago. _Not_ a good radio to start on.
    Nicely done on that one Doug, sounds awesome! Glad the skin graft went well. ;o)
    The owner did a stellar job recreating that cabinet, never would have guessed that.

    • @UncleDoug
      @UncleDoug  Před 5 lety +1

      The really tough challenges are often the best learning experiences, Shy. Thanks !!

  • @murratosmani6517
    @murratosmani6517 Před 5 lety

    This was a hard test! Glad that B+ was not connected to the input jacks and nobody has been killed.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      I'm glad too, Murrat......and a little surprised that it wasn't :)

  • @kendavis8046
    @kendavis8046 Před 5 lety +19

    Great trouble shooting and restoration of a classic amp. Thanks, Uncle Doug. If there is a future Sergio Leone, this amp can make the soundtrack! (To most young folks, that is likely a totally obscure reference.) Thumbs up!

    • @UncleDoug
      @UncleDoug  Před 5 lety +4

      You're welcome, Ken. The next time Sergio is over to visit with Jack & Ollie, I'll suggest it to him :)

    • @renegade44040
      @renegade44040 Před 5 lety +5

      Don't like to but in...but let's give credit where it's due. Ennio Morricone is Sergio Leone's composer.

    • @goodun6081
      @goodun6081 Před 5 lety +2

      A modern Sergio Leone movie will be titled *Twice* Upon a Time in the West. The music will be by Eno Morracowbell.....

    • @kendavis8046
      @kendavis8046 Před 5 lety

      @@goodun6081 He has a fever! And the only cure is Morracowbell.

    • @leonardodic3po607
      @leonardodic3po607 Před 5 lety +1

      It seems like the wiring of this amp was done by Sergio Aragonês!

  • @PrinceWesterburg
    @PrinceWesterburg Před 5 lety +4

    Ace video - its nearly 3am but I'm so happy! Thanks for the plate current maths and tremolo mods, much appreciated.

  • @DarthEcoli
    @DarthEcoli Před 5 lety

    "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts.
    " There's a good reason many of us choose to continue to learn before jumping into something we might make a complete mess of. Bertrand Russell couldn't have spoken truer words regarding this mess. Thank the gods you're a great troubleshooter.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Nice quotation, Paul......and never more accurate than in today's society.

  • @dalerobinson3091
    @dalerobinson3091 Před 2 lety

    Wow, a lot of wiring errors you tracked down; great work. The amp owner will appreciate the reborn amp.

    • @UncleDoug
      @UncleDoug  Před 2 lety

      It was a real challenge, Dale. Thanks.

  • @budandbean1
    @budandbean1 Před 5 lety +3

    Thank you Uncle Doug, this was really interesting. Excellent troubleshooting, really a fine job! Thanks for the tips about the virtual center tap too, you’ve gone over this a few times before but this time it really clicked. I just happen to have a solid state PA amp that has been humming a tiny bit since I bought it years ago that I’m going to see it this might knock that hum out of. Greatly appreciated, Buddy

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Buddy. Thanks for all your very nice comments.

    • @Magikflame
      @Magikflame Před 5 lety

      @@UncleDoug I've just thoroughly enjoyed watching this vid and subbed. Yes I came across this type of thing many many years ago where there was a say 220 ohm pot across the filament winding with the wiper to earth marked as a.... Humdinger !!!! which I believe was in an old reel to reel....

  • @jagtone
    @jagtone Před 5 lety +7

    Some people who never crank the reverb to that extreme will sub a 2M2 for the 3M3, which gives a more useable range for the reverb and gives the amp a bit more gain. But 3k3--OMG, no. Anyway, nice job on the forensics and the fixes. What great amps those are.

    • @UncleDoug
      @UncleDoug  Před 5 lety +2

      Thanks, Ben. Good advice :)

  • @Tonetwisters
    @Tonetwisters Před 2 lety

    Not an amp tech here, but much agreed on the improved sound of mis-matched Output tubes ... I came from the old school where we knew nothing about matching tubes ... we just used what we had and made it work.

    • @UncleDoug
      @UncleDoug  Před 2 lety

      Thanks for your supportive input, TT.

  • @Mauitaoist
    @Mauitaoist Před 4 lety +2

    I just finished rebuilding my Princeton thanks for all your help I have a 1966 original vintage

  • @daleburrell6273
    @daleburrell6273 Před 4 lety +6

    27:31...the amplifier hums because it doesn't know the words(?)

  • @UBOOFTB
    @UBOOFTB Před 5 lety +13

    Dear UD. It is Saturday afternoon, 1955. The band is practicing for the dance that night, and the tube dies in my amp. What do I do? I go down to the drugstore and buy a tube, pray when I put it in the amp it will work.Thank God, it works!. I can play at the dance tonight. Didn't even think about tube matching for a minute. :>) I love your videos don't ever stop!!

    • @UncleDoug
      @UncleDoug  Před 5 lety +10

      Those were the days, UB. I remember the big tube tester at the local Gunning Casteel (drug store) where you could test your tubes and buy new ones for 50 cents apiece.

    • @grb1184
      @grb1184 Před 5 lety +2

      @@UncleDoug My dad Ray had one at his stores, Colony Drugs and before that Orange Hill both in St. Pete Fla. My love for his love of this stuff brought me here.

    • @WileECoyotey
      @WileECoyotey Před 5 lety +2

      I remember tube testers in the 5&10 stores and Ace hardware .

  • @ourlifeinwyoming4654
    @ourlifeinwyoming4654 Před 6 měsíci

    It's amazing how connecting wires where they're supposed to go improves tone. This little guy was worth the effort - sounds amazing!

  • @timothyandrews2157
    @timothyandrews2157 Před 3 měsíci +1

    Awesome Job Uncle Doug. I'm appreciating your videos so much more, after slowly putting what you've taught me through the years, to good use. Thanks again.

    • @UncleDoug
      @UncleDoug  Před 3 měsíci +1

      Thanks, Tim. The learning process is definitely cumulative :)

  • @bemi-ton
    @bemi-ton Před 5 lety +3

    luckily enough there was no (virtual) center tap before as the plate was shorted to the filaments ;)

  • @stratdude83
    @stratdude83 Před 4 lety +5

    The bias is set to about 900 watts! That had me rolling 😂

  • @MajRatbag
    @MajRatbag Před 5 lety

    Great job Doug and very nicely tuned tremolo and reverb, sounds excellent.

  • @davidausterman5915
    @davidausterman5915 Před 4 lety +1

    ...and botched. I'm glad to see you resurrected this one before the bad re-wire job finished off what the house fire started.

  • @justinoneil6971
    @justinoneil6971 Před 5 lety +3

    Hey, I talked to Jack Allen today about Darrel Braun’s review of the Stage Right 15 watt. He mentioned sending you some stuff and here we are...opening it up! What a crazy world we live in today

    • @UncleDoug
      @UncleDoug  Před 5 lety +1

      Yes, Jack was kind enough to send me the Alamo Futura and reverb tank shown in the video. It is indeed a small world.

    • @justinoneil6971
      @justinoneil6971 Před 5 lety

      Uncle Doug I can make it even smaller, or at least more coincidental. I, too, live in Oklahoma and my son is named “Jack Allen O’Neil”
      Almost spooky.

  • @chrisleech1565
    @chrisleech1565 Před 5 lety +3

    Just had an idea for a series Uncle Doug, how about a Build-along-with-Doug ...DIY_Tube_Amp and one effects pedal. Plus a Speaker box or integrated like the Princeton etc.
    One of my favorite amps is the Roland Jazz Chorus 120 and I would love to make a smaller version of same for instance. It has stereo chorusing between each of its twin 12" speakers OMG it sounds good!!
    You could consider a thru hole kit build from Aliexpress maybe. Just a thought, but you could manage several vids out of that venture and have a blast at the same time.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks for the suggestion, Chris. I have posted several video series that show all the steps in building an amp at home......strictly all-tube and point-to-point wiring.

    • @Murry_in_Arizona
      @Murry_in_Arizona Před 5 lety

      Doug how tough would it be to modify a standard tremolo ( Ive got a 65 princeton reissue) or build a seperate pedal for the early 60's harmonic tremolo? I think the Lads at That Pedal Show with blues player Joey Landreth started a trend last year when they featured Joey and his vintage amps as a half a dozen new pedals with harmonic tremolo have come out.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      If by Harmonic Tremolo, you mean the Fender circuit used in amps like the Brownface Concert, it would be a somewhat challenging multi-tube build. I would recommend that you watch my video on building a Rick-Tone Tremo-Boost. It's a relatively easy build with an inexpensive power supply and great tube tremolo effect.

    • @Murry_in_Arizona
      @Murry_in_Arizona Před 5 lety

      @@UncleDoug "Harmonic Tremolo" is the part that's fascinating me U.D. The amp in question was a brown 1960 Super. Supro makes a pedal that approximates it ($250-$300) I'm at the beginner stage probably not a beginner project. FTR I've watched most of, if not all of your episodes ;0) long story short, I'm a 60 yr old retired/disabled Phx cop somehow Andertons music UK showed up in my YT feed 3 years ago and I got hooked on their guitar paradiso episodes which lead to following Mick Taylor to That Pedal show which lead to you and D-Labs when I started investigating tube amps after taking the guitar back up (starting as therapy for my hands after spinal cord injuries) after a 35 year hiatus.

  • @blairmulhall9259
    @blairmulhall9259 Před 3 měsíci

    Uncle Doug is an invaluable resource, his note not to screw the reverb tank down too tight is on the money. I was once trouble shooting a reverb circuit that was feeding back uncontrollably and loosening the hold down screws solved the issue.

    • @UncleDoug
      @UncleDoug  Před 3 měsíci +1

      Thanks for your kind words and helpful input, Blair.

  • @glenncollins4778
    @glenncollins4778 Před 4 lety +1

    Truly a joy to listen to and watch Uncle Doug

  • @0richbike
    @0richbike Před 5 lety +19

    A little bit of knowledge...
    Did the "rewired" amp start the fire?

    • @UncleDoug
      @UncleDoug  Před 5 lety +6

      If it had been allowed to remain "on" for very long, I think the unbiased 6V6 would have probably incinerated the entire block. Actually, I think it was a house fire and the amp, which was in good shape at the time, was a victim......not a cause.

    • @russellesimonetta3835
      @russellesimonetta3835 Před 5 lety +1

      Like uncle doug sez if the amp looks altered keep the fire extinquisher handy and the fire department on speed dial.

    • @goodun6081
      @goodun6081 Před 5 lety +3

      @@UncleDoug , I personally know of several cases where solid state, transistorized audio amplifiers or Hi-Fi stereos that were DC coupled and that did not have output relays, or even fuses, between the amplifier and the speakers, actually failed sufficiently to send full B+ ( anywhere from 35 volts to 150 volts, depending on the amplifier) through to the speakers and caused them to catch fire. Whenever we fix an amplifier like this at the stereo repair shop I work for, we add fuses inside the amp or supply appropriately-sized fuses and fuse holders and instruct the customer how to add them into the system between the speakers and the amplifier. The danger is if the stereo is left on while someone is away from home, or at night when everyone is sleeping, you risk Burning Down the House and maybe the occupants with it. Fortunately, most modern amplifiers , at least those used in a home audio situation, will have time delay relays that not only let the amplifier stabilize for a couple of seconds before turning on the output to the speakers, but that also disconnect the speaker wires from the amplifier internally if they sense a significant fault, any DC voltage that would cause speaker damage or worse. It bears mentioning that many high power PA amplifiers do not have relays and might not have speaker protection fuses either. A tube guitar amp, by comparison, is unlikely to set the speaker on fire, unless the output Transformer short circuits, however A Fault In The Amplifier can easily burn resistors and capacitors, then the wiring and the cabinet catches fire. or the tubes get so hot from lack of negative bias that they become cherry red glowing radiant heaters and set the cabinet and speaker on fire.

  • @billmiller7138
    @billmiller7138 Před 5 lety +8

    Interesting, for blues harp I've been running intentionally mismatched output tube pairs for many years. Stumbled on it accidentally and it just sounded better to me.

    • @UncleDoug
      @UncleDoug  Před 5 lety +3

      I'm with you, Bill. The reason choirs sound so good is that everyone has a different voice.....and the blend is both complex and rich.

    • @pharmerdavid1432
      @pharmerdavid1432 Před 5 lety

      @@UncleDoug Brilliant analogy, and we too love your videos!

  • @mfowler8808
    @mfowler8808 Před 5 lety

    Great video Doug your educating your viewers nicely. I love fixing these old Fender amps. Keep it up!

  • @bruceeverett1993
    @bruceeverett1993 Před 3 lety +1

    You almost( I say that with great respect) make it look easy. Glad there’s guys like you around! Thanks

  • @phonotical
    @phonotical Před 5 lety +5

    Woo

  • @drteming70
    @drteming70 Před 5 lety +6

    Hear, hear. I purposely mismatch my output tubes in my push-pull amps. More sweet 2nd order harmonics.

    • @guitarocd9984
      @guitarocd9984 Před 5 lety

      I know nothing about circuitry in amps. but was your statement based in science. Or just what you hear.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      I'm glad to hear that I am not alone in this discovery. Let's hope people become more aware of the benefits of mismatching :)

    • @UncleDoug
      @UncleDoug  Před 5 lety

      @@guitarocd9984 Both. I have seen harmonic spectral analysis from perfectly matched vs mismatched output tubes. The spectrum is more complex for the mismatched......primarily even-order harmonics. To my ear, mismatched yields fuller, more musical output. The bottom line, however, is how it sounds to you. Do your own experimentation and see what you think.

    • @guitarocd9984
      @guitarocd9984 Před 5 lety

      Okay I only commented because this was a new one on me. Good to know I'll definitely try it. My dad used to laugh at me when I used to tell him there is a difference in tubes. He was old school. He was dealing with televisions and Ham radios not guitar amplifiers. He's passed on but I never could convince him.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      @@guitarocd9984 Don't be afraid to experiment with speakers either. Try a ceramic and an Alnico in the same 2 x 12 enclosure. You'll be surprised by how great they sound together.

  • @strangersound
    @strangersound Před 5 lety +1

    Best teacher ever. Thanks, Doug. You make a circuit easy to understand. :)
    As for the people who wasted money on an incompetent tech...the end result is seeing Doug fix it and teach us the whole she-bang and then some (43:00). So, I'd say that was money well spent. :)

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks so much, SS. We really appreciate it :)

  • @mgb961
    @mgb961 Před 4 lety +1

    fabulous educational video...so generous..many thanks

  • @W.E.
    @W.E. Před 5 lety +8

    04:07
    How does a Fender amp chassis code of A 22264 mean 1969?
    Inquiring minds want to know. :)

    • @erikjohansson1814
      @erikjohansson1814 Před 5 lety +2

      Wayne Elliott I’d love to know the answer too...

    • @budandbean1
      @budandbean1 Před 5 lety +7

      You have to look this one up. Fender Silver-face Princeton Reverb amps with code A21500 to A25500 were built in 1969. I have a little cheat sheet but there are tons of web sites that list the Fender number scheme.

    • @UncleDoug
      @UncleDoug  Před 5 lety +6

      Thanks, Buddy. You are right on the money :) Since the serial number was close to 21500, you can assume it was made early in the year's run.

    • @W.E.
      @W.E. Před 5 lety +4

      @@budandbean1 Thanks guys;
      I had looked at this page superficially:
      www.superiormusic.com/page195.htm
      ... and saw "S" relating to 1969, but ...
      if one goes further down on the page on
      the right, the TRUTH will be found!

    • @budandbean1
      @budandbean1 Před 5 lety +1

      @Wayne Elliott You know, if I had read that page, written like it is, I’d be a bit confused too. 😉

  • @billedwards2657
    @billedwards2657 Před 5 lety +3

    I’d bet mojotone would have a rear face plate.

    • @UncleDoug
      @UncleDoug  Před 5 lety +2

      I'll let the owner know, Bill.

    • @Starcrunch72
      @Starcrunch72 Před 5 lety +2

      @@UncleDoug Yup $24.60 SKU # 9131521

    • @Bbendfender
      @Bbendfender Před 5 lety

      @@Starcrunch72 I ordered a back plate yesterday for the amp.

  • @TheFlyingRobert
    @TheFlyingRobert Před 5 lety +1

    Thanks Uncle Doug, your energy and enthusiasm is very inspiring.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Robert :) Thanks !!

  • @thomasburnett4712
    @thomasburnett4712 Před 5 lety

    Wow! Another great learning experience from Uncle Doug. Thank so much my friend!

  • @chokkan7
    @chokkan7 Před 5 lety +4

    I'm fairly certain that Mojotone has interchangeable panels such as you're seeking, Uncle Doug. In addition, if needed, I can put you in touch with a vendor who can do these at very reasonable prices, although he doesn't attempt to do Fender copies...let me know...
    In an age of oppressive conformity such as we find ourselves, your occasional blasphemy is most welcome...

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Hopefully, the owner will follow through with either Mojotone or your source, C7, to obtain a replacement rear panel. Yes, indeed, we specialize in blasphemy......indeed, we revel in it :)

  • @hippyamp
    @hippyamp Před 5 lety +1

    Great video as always Uncle Doug. Thanks for making them.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      It's our pleasure, HA. Thanks for watching.

  • @fiddlix
    @fiddlix Před 5 lety

    You are absolutely correct about using slightly mismatched output tubes. I am glad someone else agrees with me. I'll bet Brad Lindzy would agree too.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks, David. It's time that more people became aware of this.

  • @Finom1
    @Finom1 Před 5 lety +2

    Thank you for another fantastic educational video!!! Your the best, we want more.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, F1. More is on the way :)

  • @robertcalkjr.8325
    @robertcalkjr.8325 Před 5 lety

    Thanks Doug. Nice lesson!

  • @johnsimms3957
    @johnsimms3957 Před 5 lety

    Good job Uncle Doug! I love seeing amps get repaired.

  • @sonicweaver
    @sonicweaver Před 5 lety +1

    Another stellar & entertaining restoration...nice job Doug!

  • @russellsmith4615
    @russellsmith4615 Před 5 lety +2

    Thanks for doing these videos, Uncle Doug - I've learned so much from your video tutorials - they're thorough, well explained, and entertaining. I've been doing refurbish work on 3 Fender amps of my own as well as 3 others by friends and band mates thanks to you an a couple of others who are so kind to share their wealth of knowledge.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Russell. I'm glad the videos were helpful.

  • @josephmagedanz4070
    @josephmagedanz4070 Před 4 lety

    Great save and lots of good teaching to boot.
    That's one of the things I like most about your channel.
    Thanks, UD.

    • @UncleDoug
      @UncleDoug  Před 4 lety

      You're welcome, Joseph. Thanks so much :)

  • @Finom1
    @Finom1 Před 4 lety +1

    Thank you Uncle Doug for bringing another vintage tube back from the grave, Great educational video once again,

  • @I967
    @I967 Před 5 lety

    An excellent video, as always. Thank you for sharing with us, Uncle Doug.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, 1967. Thanks !!

  • @kevinwilkins9926
    @kevinwilkins9926 Před 5 lety

    Looks and sounds good. Great troubleshooting Uncle Doug. Really appreciate you sharing these videos.

  • @albertanderson349
    @albertanderson349 Před 5 lety

    Amazing video UD! Learn something new with your explanation of that reverb resistor issue, thank you sir!

  • @ElPasoTubeAmps
    @ElPasoTubeAmps Před 5 lety

    Doug - you are awesome - so good to see you posting again.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks so much, David. It's good to be back.

  • @jordancraighead
    @jordancraighead Před 5 lety

    gives me new appreciation for printed circuit boards from a troubleshooting perspective.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      .......and yet, those of us who prefer point-to-point circuitry would say just the opposite, Jordan. Its just a testimony to the variation in individual preferences.

  • @Dennis-mq6or
    @Dennis-mq6or Před 2 lety

    Excellent troubleshooting!
    I really enjoyed watching....

  • @jasonkirkham550
    @jasonkirkham550 Před 5 lety

    Another awesome video ! And more lessons learned.
    Thanks Doug!

  • @rockgtr35
    @rockgtr35 Před 4 lety

    These are just the best videos of this kind. Excellent explanations, camera work, and commentary!

    • @UncleDoug
      @UncleDoug  Před 4 lety

      Thanks so much, Jason. We appreciate it :)

  • @wyattsdad8561
    @wyattsdad8561 Před 3 lety

    I’m always amazed watching your videos on how well you know this stuff. I wish I understood this stuff and could build an amp or something cool. But I’ll keep watching and hopefully learn something.

    • @UncleDoug
      @UncleDoug  Před 3 lety +1

      I arrived late on the electronics scene and am entirely self-taught, WD. If I can do it, you can too.

  • @sethbrandes2979
    @sethbrandes2979 Před 5 lety

    Was I the only one getting hungry with the cool whip containers in the background? Joking aside, what an informative session! I especially loved how you went back to the trace and explained why that incorrectly valued resistor back in the path was affecting the reverb's signal by not providing enough backpressure to force the signal down into the reverb circuit! Always learning on this channel!!! You rock Uncle Doug!!!

    • @UncleDoug
      @UncleDoug  Před 5 lety +1

      Thanks, Seth. I'm glad it all made sense. We do love our Kool Whip :)

  • @davida1hiwaaynet
    @davida1hiwaaynet Před 5 lety

    Your level of knowledge and patience never ceases to amaze me. Thanks for sharing this very tough repair job!

    • @UncleDoug
      @UncleDoug  Před 5 lety +1

      You're welcome, David. Thanks !!

  • @jamescarter4175
    @jamescarter4175 Před 5 lety

    Your videos are fascinating. Thanks again!

  • @nemoes
    @nemoes Před 5 lety

    Incredible work Doug!

  • @doogdoogdoogdoogdoogdoog

    One of my fave channels on CZcams; thanks so much, Doug 🙌

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Doog. Thanks !!!

  • @scott729
    @scott729 Před 5 lety

    Thanks Doc. Another fine production

  • @somewhereelse000
    @somewhereelse000 Před 5 lety

    Yet another excellent video! Thank you.

  • @Intrinsic.Recording
    @Intrinsic.Recording Před 5 lety +1

    After watching a second time with no distractions...it's little wonder there was a fire. Owner should be ecstatic with the amp now. Great job man.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      He seems to be, JP. Thanks !!!

  • @jamesbruno5896
    @jamesbruno5896 Před 5 lety

    Incredible job UD, your the man! Boy that sounds sweet! Kudos & I totally agree with the output tubes not matching that closely...

  • @daveogarf
    @daveogarf Před 5 lety

    DAMN! Your cats are SOOOO TALENTED! Their demos of repaired products are invaluable.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      I'd be lost without them, Dave :)

  • @larrydering1598
    @larrydering1598 Před 5 lety

    Doug, ws usual your dedication to details solved the problems. Great teaching information. Love your videos.

  • @Kilovolver
    @Kilovolver Před 5 lety

    It’s that time FELLAS! UD and chill! Thanks for the new up UD, this channels is about to blow, I can feel it

    • @UncleDoug
      @UncleDoug  Před 5 lety

      If by "blow" you mean exceed all expectations, then I'm down with that, K :)

  • @PLINKER
    @PLINKER Před 4 lety

    Wow sounds great Uncle Doug. your touch is just what that mess needed.

  • @birkettaustin
    @birkettaustin Před 5 lety

    so many rookie mistakes from a so called tech. another great restoration uncle doug!

  • @82abn34
    @82abn34 Před 4 lety

    Thanks Uncle Doug. Reminds me of a time I showed up to repair an electric forklift and found the house techs and already had a go. The thing was in many pieces and both techs were flummoxed. It took me several hours to reassemble before I could start the troubleshooting procedure. It turned out to be an intermittent control pot. This was always the first thing I checked for given the symptoms reported for the problem. It wasn't their fault. Their boss wanted them to take a crack at it before they called me. Those guy's were engine mechanics. They tried to save a little and winded up paying much more. Thanks to you and others, I have begun learning about tube circuits. I just refurbished a Heathkit VTVM and it works. Now I can watch a needle sweep with a high impedance meter instead of the old Simpson 260. Thanks again.

  • @waynewayne3709
    @waynewayne3709 Před 2 lety

    Very well explained and showing how it should be done.

  • @artisanmetalcraft
    @artisanmetalcraft Před 4 lety

    This video is fantastic! Great Job

  • @michaelmcginley7412
    @michaelmcginley7412 Před 5 lety

    So great! Thanks, Doug. I really appreciate how you examine and explain the schematic, and then show where it is in the actual amp. It brings the whole thing together and makes it so much easier to understand.

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Michael :)

    • @michaelmcginley7412
      @michaelmcginley7412 Před 5 lety

      Oh, and not to bother you, but I think you might enjoy this podcast. It's called "The truth about vintage amps."
      www.fretboardjournal.com/podcasts/the-truth-about-tube-amps-ep.-1/

    • @UncleDoug
      @UncleDoug  Před 5 lety

      Thanks for the link, Michael. I will check it out when I get some free time.

  • @jeremyacker1388
    @jeremyacker1388 Před 5 lety

    Uncle Doug, you are amazing! I love your videos. I just wish I had your knowledge. Thank you for explaining things and using diagrams. Please don't stop!

    • @UncleDoug
      @UncleDoug  Před 5 lety

      You're welcome, Jeremy. We won't :)

  • @spazimdam
    @spazimdam Před 3 lety

    Very good demonstration of proper repair procedure. Always a treat to watch your vids Uncle Doug; they confirm methods that I have found valuable in years of tube amp repair, and a few valuable insights that are new to me. Too cool.

    • @UncleDoug
      @UncleDoug  Před 3 lety +1

      Thanks, Monte. We're glad the video was informative.

  • @markanthony653
    @markanthony653 Před 4 lety

    This guy could be a multi-millionaire(if he's not already) the way he fixes these amplifiers, truly one of the only people I've ever seen that can fix a amp properly, and more importantly you could trust!!! Hell, I trust him with my Marshall.

    • @UncleDoug
      @UncleDoug  Před 4 lety

      Thanks so much, Mark. I'm actually working on my second million dollars......I gave up on the first one :)

  • @thome1547
    @thome1547 Před 5 lety

    Uncle Doug, great job as usual, never believe in anything others have done (or messed up). Keep it up.

  • @frogbastard
    @frogbastard Před 3 lety

    When Leo Fender made his amps,tubes were tubes,no boutique mumbo jumbo about matched tubes,especially with the loose tolerances of components.Some amps sounded better than others within the same models,but that's just the way it was.You are correct to question the hype about matched output tubes since this has become a market unto it's own and definitely brings with it a premium price.

  • @davidanderson4500
    @davidanderson4500 Před 4 lety

    what an absolute brilliant tech guy you are doug. love your videos, fab

  • @bassiclogic
    @bassiclogic Před 4 lety +1

    You are the best Amplifier tech I have ever seen! Your skill and knowledge are on an Engineers level!