BF Super Reverb in for a Tune Up.....Botched Wiring & Bad Tubes.....but a Happy Ending

In this video we will document the repair of a 1966-67 Fender Blackface Super Reverb circuit. As delivered, it had some serious wiring issues and worn-out tubes, including a 5U4 rectifier, rather than the proper GZ34. These problems allow for a discussion of repair theory as well as demonstration of the relative performance of the 5U4 vs GZ34, both with and without a Current Limiter in series. A demonstration of tremolo speed reduction is also provided. As usual, an audio demo is performed, including each of the effects......tremolo and reverb.....at various levels. We hope you enjoy it.
If you do enjoy our videos and would like to support our channel, please consider becoming a patron of our channel via Patreon: / uncledougsvintageamps or making a PayPal contribution to [e-mail]. Thanks !!!

[@Scott-rz9vw]

Having a fresh Uncle Doug video queued up on a Friday makes my weekend plans even better. Thank you for the content and expertise!

[@UncleDoug]

You're welcome, Scott :)

[@kennyh5083]

@@UncleDoug Hey Uncle Doug! Hey got a tidbit of info, on my question about solid state amps and final ohms for lower output. I have just been told from a company that yes running an ohm speaker that produces max watts does in fact stress the internals more than running it at lower watts! Seems even some Marshall would have reliability issues when running a speaker with an Ohm rating producing max watts from the solid state amplifier! I have since altered my speakers/cabs so my solid state amps run at lower watts since I really don't need the extra volume as much as I do the reliability and longevity of my amps! Take care Uncle Doug!

[@UncleDoug]

@@kennyh5083 Thanks for the info, Kenny.

[@jaysorensenIBEW]

I agree. It was a nice surprise!

[@seansweeney3532]

You should make a compilation video of your most outraged moments, because I'm sure I'm not alone in finding you at your most hilarious!

[@stevewinwood3674]

One of my favorite parts of a new Uncle Doug video is to hear what he will say about the packaging job.

[@UncleDoug]

As a result of my public unboxing scenes, the overall quality of amp packing has improved dramatically :)

[@stevewinwood3674]

@@UncleDoug most definitely. 4 out of 5 five packing peanuts comment. Course of them shifted to wrong spot :)

[@vintageguitaramp_guitarteacher]

Every time I hear the demos at the end of your videos, I get this vision of Jack standing on his back legs rockin out on the guitar. Makes me smile. Another great video. Thanks for sharing. Take care.

[@UncleDoug]

Glad you enjoy them, VGA :)

[@tomstiel7576]

I just love me sum good ole Uncle Doug,,,best channel,,still !!! I thought perhaps the feline quartet was in Mexico on spring break,,,happy to see they followed the new warnings and opted to stay home this year !!!

[@UncleDoug]

Thanks so much, Tom :)

[@tonymanns8249]

A Sidebar: I've been watching your videos for many years and dare I say that you seem to have been noticeably getting more accomplished at playing the guitar. Kudos. My playing has been getting worse the past few years due to lack of interest and avoidance. LOL

[@UncleDoug]

Then you need to find a couple feral musicians, like Ollie & Jack, to cover for you ;)

[@DerekHerbst747]

The biggest gem in uncle Doug's workshop is uncle Doug!! 👍

[@UncleDoug]

Aw shucks, Derek ;)

[@dhpbear2]

24:03 - That's the FIRST time I've seen (and heard) a Gain vs. Bias demo!

[@UncleDoug]

We try to go where no one else has gone before, DH ;)

[@steverhenius6734]

Enjoyed the playing on the demo :-)

[@UncleDoug]

Thanks, Steve. I'll share your compliment with Ollie & Jack.

[@steverhenius6734]

They’re probably Nashville cats :-)@@UncleDoug

[@UncleDoug]

No doubt :)@@steverhenius6734

[@markvincent522]

Heck yeah! Uncle Doug is the man! He's the uncle we all wish we had. None of my real uncles do anything this cool.

[@UncleDoug]

Thanks, Mark :)

[@GroverCricketDaisy]

Thanks for a great video with so much interesting information.

[@UncleDoug]

You're welcome, Grover.

[@chrisfournier6144]

Awesome resurrection of this worthy amp Uncle Doug! And I mean three paws awesome, you’re a real gone cat!

[@UncleDoug]

Thanks so much, Chris :)

[@nomadicnerd818]

Pizza, beer, and a new Uncle Doug video. This is turning out to be a good Friday night!

[@UncleDoug]

Bon Appétit, NN :)

[@rohankhemraj]

It's nice to know that even badly botched amps can be brought back to life. Thanks for sharing the repair and your knowledge.

[@UncleDoug]

You're welcome, Rohan. They're all "fixable" :)

[@woodys_hobbies]

Hello uncle Doug!!! more power!!!!!!!!

[@UncleDoug]

Hi, Woody. Always !!

[@vintagetubeamplifiers]

What a great day! Happy St. Patrick's Day, Uncle O'Douglas.

[@UncleDoug]

Thanks. Likewise, VTA :)

[@thenameless3271]

Ironic that they should destroy the safety sticker lol We love ya Uncle! Even when I don't necessarily understand what's being done, your videos are always worth the watch!

[@UncleDoug]

Yep, they went right for the most ironic spot on the panel :)

[@lanehaverly4332]

Allways love your comtents and Saftey notes we all need a smile have a great day

[@UncleDoug]

I'm glad to hear it, Lane. Thanks.

[@stevenclarke5606]

Uncle Doug, the best and most entertaining amp technician in You Tube Land. Thanks for another great video

[@UncleDoug]

Thanks, Steven :)

[@lynnagan7347]

Always something to learn and do…. May God bless you Uncle Doug.

[@UncleDoug]

Thanks, Lynn.

[@danielsaturnino5715]

Thanks Uncle Doug

[@UncleDoug]

You're welcome, Daniel.

[@raycochrane3971]

Uncle Doug does Led Zep & does it well. Cool results - repair of repairs.

[@UncleDoug]

That's Ollie's specialty, Ray.......she's a big fan of Jimmy and the gang :)

[@jeffthevideoguy23]

Uncle Doug is the Socrates of the amplifier, the Plato of plate current!

[@UncleDoug]

Wow, thanks, but you forgot the Aristotle of Amplification, Jeff ;) ;) .

[@jeffthevideoguy23]

@@UncleDoug I knew I forgot something!

[@UncleDoug]

@@jeffthevideoguy23 The Catherine the Great of Cathode Bias ;)

[@jeffthevideoguy23]

@@UncleDoug the Atilla the Hun of hum cancellation.

[@UncleDoug]

@@jeffthevideoguy23 "Atilla the Hum" :)

[@duanerogers5391]

That 3 wire power cord was installed backwards. Brown was hot and blue neutral. Glad you changed it!

[@UncleDoug]

It was a mess that had to be redone properly, Duane.

[@mobicus1]

It's always a good day when a new Uncle Doug video comes out! Thanks again, Uncle!

[@UncleDoug]

YW, Rick.

[@bobdeescosmosis]

"We love a challenge (not really)!" LOL Very funny Uncle Doug! What a mess. Amazing work!

[@UncleDoug]

Thanks, Bob :)

[@JFredick]

Great to see you back Uncle Doug!

[@UncleDoug]

Thanks, JF :)

[@paulvale2985]

I retire at the end of March (2023) and now Tom has the answer to my lost tool/cluttered bench problem! The best ideas are the simple ones; great thinking Tom.

[@UncleDoug]

Glad you liked the invention, Paul.

[@robertburch2196]

The mains cable is from a European source. The brown is Live/Hot and the Blue is neutral return. Green/yellow is the earth. Europe, UK and surrounding area usually run from 220v AC 50Hz. Thank you for your really valuable videos. I have spent many hours watching with a great deal of fascination. I do the same kind of work here on a much smaller scale, in the UK and likewise, have found a great many short cuts other 'technicians' have cobbled together to try and make things work. Consequences can be really significant.

[@UncleDoug]

Thanks for your input, Robert.

[@markbunch5062]

I love your videos. But I really wanted to thank you for just saving me a whole lot of money... I have just been able to diagnose my own amp and the only reason was your superb and patient explanation of amp wiring schematics. I had no previous knowledge of electronics but what I have absorbed through watching just about all of your videos, let me track down where I thought I had a problem and realise that there was a simple fix with no changes needed. Yesterday I was busy pricing up new amps and today I'm back murdering 'Free falling'! You've made a real difference, Uncle Doug. Thank you.

[@UncleDoug]

That's really great to hear, Mark. We're so glad our videos are helpful and informative.

[@mohamedtlass3842]

Love how you put green river riff in the demo! You must see John Fogerty for his celebration tour!

[@UncleDoug]

Thanks, Mohamed. I would love to......he's one of my major heroes.

[@scottmulrooney3130]

Always a great day when an Uncle Doug video shows up in your feed. A million thanks for sharing your expertise with all of us UD heads!

[@UncleDoug]

Glad to hear it, Scott. Thanks !!

[@dougulman6700]

I was too busy to wacth this at least that's what I told myself for the first 15 minutes and then forgot what i was supposed to be doing, you make it so entertaining as well as educational! Thank you

[@UncleDoug]

Glad to hear it, Doug.

[@KB_Joys]

Another classic American amp brought back to life from Uncle Doug. I finally figured out what one of those hooks was that you play sometimes in your videos, Brian Adams Run to you. I had thought to myself and checked on KZbin and sure enough, lol. Thank you for the video. ☺️

[@UncleDoug]

Thanks, KB. Yes on the BA tune :)

[@billsoule5824]

Hi, Uncle Doug - Great video, I just want to bring up one cautionary issue in that you are utilizing that Elenco 440 substitution box you received from a viewer on an earlier video. I wanted to point out that this cap box is made from cheap 50V & 100V caps of which after a few years they are finally admitting that in their advertisements, 100V max. Could be quite a bang for people seeing this video and figuring " you use that box all the time, I need to buy one." You may want to put a disclaimer somewhere. Don't want anybody dialing in a corner frequency on an interstage dc block. 😉 Again, always enjoy the videos!

[@UncleDoug]

Thanks for your helpful input, Bill.

[@benoySimon]

Uncle Doug - Thanks so much, you are such a blessing. A dedicated follower of your channel and content from Austria. Just to say a big 'THANK YOU' - Your'e the world's best teacher, with your very simple style, even dummies like me cannot fail to understand the fundamentals of electronics, and so casually peppered with great humor. God Bless you!

[@UncleDoug]

Thanks so much, Ben. We appreciate your kind words :)

[@JammyCrackcorn]

Hadn’t chimed in since late 2022…After you installed power cord, that white wire scared me lying against the 6L6 socket and also the screw threads…Love the video!! You are the Beat!! Still working on my 68 Fender Bassman

[@UncleDoug]

I'm sure I corrected the wire routing eventually Jammy. It's good to hear from you :)

[@alvarofalcon7136]

Great video as usual Uncle Doug! Every time I see you have a new video out I’m happy and relieved that you’re still in good health and working on those great amps! Best Rgds

[@UncleDoug]

Thanks, Alvaro :)

[@julesl6910]

Fantastic video. Gotta love Blackburn made tubes.

[@UncleDoug]

Glad you enjoyed it, Jules.

[@dokterzorro]

Yeah! Uncle Doug on fridaynight TV! Life's good!

[@UncleDoug]

Thanks for watching, Doc.

[@josephsichting8162]

I'm also giving thereof my paws up on this one, Uncle Doug!

[@UncleDoug]

Good grief.....are we worthy of such praise ?????

[@phillipyannone3195]

Nice job on that beauty. No drama just cool confident experience. Looking forward to your upcoming video.😊

[@UncleDoug]

Thanks, Phillip :)

[@michaelmerritt1722]

It's good to see an amp tech that knows what they are doing! Another great video Uncle Doug!!!

[@UncleDoug]

Thanks so much, Michael :)

[@hv8546]

Best YT channel ever, thx once again, Uncle Doug.

[@UncleDoug]

Thanks so much, HV :)

[@m1km1sh1n]

Oh, good uncle Doug is back on the line! I really like your detailed descriptions of the failures of ancient American amplifiers. I myself am repairing tube amplifiers in Europe, and your comments are very useful to me sometimes. Thank you very much for your selfless exchange of useful information!😁👍

[@UncleDoug]

You are quite welcome. Thanks for watching :)

[@bluesingmusic3443]

So happy to see a new video, made my morning. Such a shame about the hammer mechanic who worked on the wiring, & of course the carnage on the back. Still it would be a nice amp to gig with, so all is not lost.

[@UncleDoug]

Thanks for watching, BiG.

[@goodun2974]

You can buy replacement front panels for a blackface Fender, but I don't know if reproductions of the rear panels are available....

[@UncleDoug]

@@goodun2974 Nor do I, GU. My advice would be lots of internet searches.

[@adenihil]

I also grant you 3 paws up Uncle dude! Well done and thank you! ✌🏼

[@UncleDoug]

High praise indeed, A :)

[@bellasvistas3463]

Rainy morning here a good coffee and a great video to watch. Thanks

[@UncleDoug]

We hope you enjoy it, BV.

[@alexdeleon7135]

A great demonstration of corrective surgery, Uncle. The previous reprobates ("techs") were reckless, amateurish, and incompetent. It was a complete joy to experience the process in diagnosing the mistakes that were made, and explaining your detailed flow chart of the modality you employ in the step-by-step approach to repair the circuit by compartmentalized order. Thank you for posting! I await this next episode with great eagerness. Enjoy you weekend, uncle. Stay safe and in abundant health.

[@UncleDoug]

Thanks so much, Alex. Glad you enjoyed it. Likewise on the good wishes :)

[@erin19030]

I bet you cant even solder without burning yourself.

[@simongotlieb2560]

What a wonderful surprise to see this show up in my feed. Thanks Doug. You made my day.

[@UncleDoug]

Thanks for watching, Simon :)

[@edwardkujawa]

Uncle Doug you are a class act so through with your videos God Bless always from a fellow electronic tech

[@UncleDoug]

Thanks so much, Ed :)

[@richreid7098]

A new UD video! Always a treat!

[@UncleDoug]

We hope you enjoy it, Rich.

[@meesterprofe007]

What a great way to start my morning! Thanks for posting this video on an led b.f. Super Reverb....I have one and love it🎸

[@UncleDoug]

Glad you enjoyed it, MP.

[@matthewzimmerer3329]

Hey, thanks so much for everything you do Uncle Doug. I've really learned a lot.

[@UncleDoug]

Good to hear, Matt :)

[@treborheminway1196]

Uncle Doug, I think had you checked, you would have found that those are UL certified reference pillows. Pure gold. That amp was tucked in lbetter than a TJ Tuck and Roll special. Note: The three wire power cord wiring was coincidently also done in TJ, but in the red light district. Hot Chihuahua!

[@treborheminway1196]

As always, thank you very much for all the expert discussion on how to do it right.

[@UncleDoug]

Thanks for opening my eyes to just how special the packing material was, Trebor. I'm tempted to sell it on Ebay ;)

[@tonymanns8249]

I'm a retired electronic technician and I love your amp videos, and your wit. Breaks my heart and I always say a eulogy for every vintage electrolytic capacitor that has to be sent to the graveyard. lol My '69 Fender Bandmaster & '73 Super-Reverb still have all of their electrolytic caps except for two power supply filter caps in my '69 Super-Reverb.

[@UncleDoug]

Thanks, Tony. In my own amps I tend to preserve original components, but I just can't do that with customer amps......unless specifically requested to do so.

[@tonymanns8249]

@@UncleDoug I like to to keep vintage stuff when I can. But, yes, your modernizing of old amps will for sure benefit your customers to enjoy an amp that will be very reliable for many many years. Leo Fender in my opinion made the beast amps ever made with the Blackface amps. Dumble was the next evolution of tube amps. I own a Dumble clone amp and I love it.

[@soundcityec]

I miss you uncle Doug! I hope you and your loved ones are well. I have this exact amplifier and your video helped me a lot. Recaped, new power cord, and modded the tremolo with that 0.2 cap =) I'm loving those MOD caps. I have used them in 1 princeton (also help from your video), two Twin Reverb SF, and now this Super reverb but mine surely has the center tap for the 6.3v

[@UncleDoug]

Thanks for the kind words, Daniel. We will have a new video posted in the next couple weeks :)

[@patoneill3373]

great to see you back.

[@UncleDoug]

Glad to be back, Pat. Thanks.

[@JoshRoberts-fo5gq]

Awsome as always....never disappointed uncle doug

[@UncleDoug]

Glad you liked it, Josh :)

[@tiborbogi7457]

What a cool audio demonstration! Once I sit down and solve all song snippets you play ;-)

[@UncleDoug]

Glad you enjoy it, Tibor :) Some are Jack & Ollie Originals.

[@davidapharry4680]

So nice to see you working your much needed magic once again!

[@UncleDoug]

Thanks for watching and commenting, David.

[@mitchmorris4998]

I was super excited when I got the notification about another video from Uncle! You are a great teacher Uncle Doug! No doubt you know your stuff!! Thanks for sharing your gift!

[@UncleDoug]

Thanks for watching and commenting, Mitch.

[@SuburbanDon]

Its always nice to wake up with uncle Doug. Well, you know what i mean.

[@UncleDoug]

We can share the packing pillows, Don.

[@marblelee]

Uncle Doug you are the best thing on KZbin.

[@UncleDoug]

You are too kind, Cade......but thanks ;)

[@russlora]

New Video !! wooohoo!! Go Doug ! I love working on old amps

[@UncleDoug]

Thanks, RV. Me too :)

[@doctorcircuit5338]

Thank you for all these videos over the years even an old tech like me can learn something new from you

[@UncleDoug]

You're welcome, Doc :)

[@sgt.grinch3299]

Great sounding amp. I love P-90s. They are my favorite pickups. Well done Sir, this will last a long time and give great joy to many.

[@UncleDoug]

Thanks, Sarge. I sure hope so :)

[@seansweeney3532]

Gotta love the mullards! Working on hammonds as i do i always check the junked organs and found a trove of Mullards and vintage RCA tubes, amperex bugle boys, those Hammonds always were stocked well, amd most of them were very mild voltages, so they'll still rock your guitar amp after 50+ years in a Hammond!

[@UncleDoug]

Hammond definitely didn't scrimp on tube quality, Sean, much to our harvesting pleasure.

[@mechanoid5739]

Well! That amp was a diamond in the rough! Sounded beautiful after all your work Uncle Doug!

[@UncleDoug]

Thanks so much, Mech :)

[@gniac]

Good to see you back sire !🙂

[@UncleDoug]

Thanks, G :)

[@v12dot]

Another Gem UD 👍🏴󠁧󠁢󠁳󠁣󠁴󠁿

[@UncleDoug]

Thanks, Stewart :)

[@timbuckxxi9690]

Good day..A fresh Uncle Doug.. And a amp about to be a SUPER REVERB again..Coffee time..

[@UncleDoug]

Glad to hear it, Tim. I'll join you :)

[@timbuckxxi9690]

@@UncleDoug Rescued that one..The power cord was way too sketchy..No wonder it got toasty.. A strat with P-90's ? Nice..And Doug your're playing some interesting songs..

[@phillipbainbridge9107]

An Uncle Doug video? That's unpossible!

[@UncleDoug]

.....but it's true, Phillip.

[@Cleofizoid]

Can't wait for the next video! I'm going to guess a 1959 Tweed Twin.

[@UncleDoug]

Smaller, rarer, but about as costly.

[@SkyscraperGuitars]

It''s always a treat to tag along on your repair adventures UD!

[@UncleDoug]

We enjoy your company, SG :)

[@VolkswagenVMan]

Awesome job and great video as usual!!!!

[@UncleDoug]

Thanks twice, VWM.

[@DrHumbertoable]

Thanks again for spending time and work to let us take part. I am following your content for a couple of years now and never have been disappointed.

[@UncleDoug]

Our pleasure, Doc. Thanks for watching.

[@MegaTubescreamer]

what looked like some kinda black nightmare at the start ,, sounded like a technicolour dreamscape uncle doug, the slower tremolo and a touch of reverb was so relaxing and easy on the soul, incredible job beautiful tone ! 😇👍🎼

[@UncleDoug]

Thanks so much, William :)

[@stirlingschmidt6325]

Always good to see you back! Have a good weekend!

[@UncleDoug]

Thanks, Stirling. You too.

[@VegasCyclingFreak]

Nice job fixing that hack job Uncle Doug!

[@UncleDoug]

Thanks, VC :)

[@tomw9875]

Thanks Uncle Doug!

[@UncleDoug]

You're welcome, Tom.

[@scott729]

Appreciate you Uncle Doug

[@UncleDoug]

The feeling is mutual, Scott.

[@mj-dd2fb]

Thanks, Uncle Doug!👏👏

[@UncleDoug]

You're welcome, MJ.

[@PipeCat1965]

Another amazing rescue. Can't wait to see what the next one will be.

[@UncleDoug]

Thanks, PC. Stay tuned :)

[@richardwhite7247]

The Feral Quartet love their catnip, but for me a new UD video beats Nepeta cataria hands down. Wonderful dissection and resurrection of this great vintage amp. Well done as always. Now the only question is: what do I do until the next one comes out? Guess I could always listen to some Hank...

[@UncleDoug]

Thanks so much, Richard. Never fear, a new video is on the way :)

[@J.C...]

Nice to see you, Uncle Doug! 👌

[@UncleDoug]

Thanks, JC. It's good to be seen :)

[@fredcoston6580]

Thanks again for a great amplifier lesson , as always

[@UncleDoug]

Thanks for joining us, Fred.

[@rhoneranger549]

I am probably one of your rare viewers that knew what you meant by "drunk chimpanzees" This is a terrible rebuild, no wonder it was all messed up. Thank you again for sharing all your knowledge with us out here in youtube land. BTW saw on Facebook the kitties :) Glad to know you and be your loyal follower for many years.

[@UncleDoug]

Thanks, Matthew. On one hand, it's flattering to receive repair jobs that others can't handle.....on the other hand, every such job is a major challenge, beginning with undoing all the previous harm.

[@GL64]

Excellent as always!

[@UncleDoug]

Thanks, GL :)

[@lrdisco2005]

What a result, we are both above ground. I am working on getting my head to work properly again, and you are a very positive influence. Thanks.

[@UncleDoug]

Best of luck, LR. We hope we can help.

[@davidfellows6250]

wow that saying something. "one of the most special amps we've had". can't wait for that considering the amps you've already had. thanks again for being commercial free. you have no idea what that means to me. ive got alittle Neil Young in me too.

[@UncleDoug]

You're welcome, David. The moment you accept advertising, you open the door to external control of your video content. I really don't need any "partners" in my little video enterprise :)

[@davidfellows6250]

@UncleDoug i killed all my channels when they started advertising on them. not only do you get a partner but you are endorsing whatever crap they choose. love ya uncle.

[@alvarofalcon7136]

Your new guitar sounds great and very in tune!

[@UncleDoug]

That's good to hear, Alvaro.

[@chrislayman4142]

Hi Uncle Doug! I have been subscribed to your channel for a few years now and have picked up a bucket load of information on the workings of guitar amps. l want to thank you for being a wonderful teacher and preventing me from zapping any of my remaining hair off! l love listening to your verbal cantor but if you think your having a chilly day feel free to visit us up here in Canada! Lol! Thanks again and l look forward to many more videos. By the way l also like your hot rod stuff!

[@UncleDoug]

Thanks so much, Chris. By coincidence was really cold and windy.....at least by West Texas standards.......so no trips to Canada are necessary ;)

[@darkobrankovic4979]

But none the less I still enjoy watching your videos

[@UncleDoug]

Good to hear, DB :)

[@kane100574]

Sweet

[@SteverRob]

That was a botched power cord install you found, Unc. The blue is neutral, brown hot. So the hot side was fused and looks like the neutral originally went in and out of the two outlet lugs, so the amp wouldn't ever turn on unless something was plugged in to that outlet, and being in series with the neutral, whatever was plugged in wound up being a current limiter. After the fire, someone then moved the neutral to the same lug.

[@UncleDoug]

Thanks for your analysis, SR. It was indeed a mess.

[@MrMousekillaz]

Hi Uncle Doug!

[@UncleDoug]

What up, M :)

[@rgbplumbinghilton]

Another great video. Without doubt, you Doug are the King of You Tube as far as amp repairs go. I watch them all and no one comes close 👍 I am already looking forward to the next one!! Rich

[@UncleDoug]

That's great to hear, RGB :)

[@Rod_Knee]

Another informative, educational and entertaining episode, Doug. Thanks.

[@UncleDoug]

We're glad to hear it, Rodney. Thanks :)

[@Splattle101]

Cool old amp. Nice job on the repair, too. 👍

[@UncleDoug]

Thanks twice, BS. Your name reminds me of a previous Silvertone video.

[@PennStacker]

Thanks for another great video!! Missed you

[@UncleDoug]

Thanks, Mark.