I started checking my KZread subscriptions for this video the moment I mailed it in. Thanks for going to battle! Watched the video - outstanding work UD! To answer a few questions: I know what you're thinking and yes, this amp was not worth repairing. The fact that UD fixed it not only demonstrates his remarkable skill, exceptional teaching gift, and sense of humor, but also showcases his willingness to help. I asked him to proceed as a cautionary tale for his viewers. He spared my pride a lot in the video. I'm a cheapskate and the amp was an eBay purchase that seemed like a deal. I thought I could save a few dollars by buying one that was "fixed", but needed "finished" with new tubes and the poorly recovered cabinet rectified. It came with some old parts the proved it was fixed. It arrived and powered on with a hum, but it scared me so bad, I locked it in a closet for a while. Eventually I bought new tubes and an unmolested original cabinet. Of course the new tubes didn't help much so I bought what I thought was a new hum balance pot to fix the "minor hum problem" that remained. It became clear that the amp was very sick. So much so that when I turned the volume knob up the shower faucet came on. So I bought a replacement for the missing foot switch and then I bought casters for the cabinet. This also didn't fix the amp. With what I spent on parts etc, I could have bought a nice known-good non-MV Twin. I may be cheap, but I'm not a quitter, so I gave up and mailed it to UD because at some point knowing what was wrong with the amp became just as valuable to me as the actual amp. Furthermore, I didn't want a MV Twin Reverb, which is why I bought one in the first place… Like many, many others, I wanted it removed so I asked Internet. Instead of answering that question, Internet answered another, different question - "set it to 10 and ignore it". UD answered the actual question and documented it. To my fellow cheapskates: don't be like me. Wait for the right amp. Contrary to what your brain may tell you, it's actually cheaper to spend $1000 one time than to spend $200 10 times over the course of two years.

@UncleDoug

5 жыл бұрын

Thanks for your very honest and illuminating commentary, K. This amp is indeed an excellent lesson in the British term "false economy", in which an apparent bargain can often turn into a bottomless pit of expense and frustration. In this case, it WILL work.....but as we both discovered, the effort and expense are far in excess of what should normally be required to resurrect a vintage circuit.

@MrChopin2323

5 жыл бұрын

I have this amp too that I am about to go to battle on! I haven't even started the video yet and I am super excited.

@UncleDoug

5 жыл бұрын

I hope it lives up to your expectations, Mr. C.

@slash5bmw

5 жыл бұрын

I forgot to mention in my comment above that just the MV removal demonstration is worth some financial support for UD. For those of you wondering, it takes hours of his time corresponding, researching, repairing, recording and editing to produce these videos. And he gives away this effort and knowledge for free. Please consider showing your appreciation.

@johntempleton6368

5 жыл бұрын

Everyone that has owned or fixed a number of amps for a long enough time gets one just like this. Twin chassis, complete, $200 OBO.

I'm just a guitar player but now I know what my amp tech is going through when I bring in my Fender for service. He is worth every dollar I pay him. Can I get an Amen.

@UncleDoug

2 жыл бұрын

Yes, you can :)

Dear Uncle Doug: You're not fooling me. You loved every minute you hated it. So did we. Thanks for the hard work.

@UncleDoug

5 жыл бұрын

I guess you got me there, Rowdy. There is no gain without some pain :)

@graxjpg

5 жыл бұрын

Uncle Doug If my bowels fall out of a gaping wound in my abdomen, can I then count that as an immense gain?

@wildbob

5 жыл бұрын

@@UncleDoug Ooh guitar amplification puns. I have to steal that.

@Steven9675

4 ай бұрын

⁠ Well done , resurrection can be time consuming, and yes…. Difficult. It is a good feeling after it is over. The cringe you must have felt when you saw the extent….. and then the noise at the end as it gave up….. 😊 I feel your pain.

Loved Jack's disappearing trick. He's a real character.

@UncleDoug

5 жыл бұрын

He is a master of concealment, Sean :)

@DMC428

5 жыл бұрын

A real ninja! 😁

@goodun2974

5 жыл бұрын

Sean Kerns , cats move seamlessly back and forth, multiple times a day, from the visible world to The Upside Down dimension.

@daleburrell6273

4 жыл бұрын

@@goodun2974 ...possibly.

Thank you Uncle Doug, Bless you for sharing your wisdom with us!!!

@UncleDoug

5 жыл бұрын

You're welcome, F1. Likewise on the blessing :)

This is way over my head, but it's nice to know that there's still someone out there that still understands this stuff. I remember my friends did their own repairs on their amps/guitars in the 60-70's.

This guy is so fun and entertaining with his dry humor, I could hang out with him all day.

@UncleDoug

Ай бұрын

Thanks, Luke. You're always welcome :)

Bless your patience in cleaning up someone else's mess, great job. Thank you for sharing the knowledge Uncle Doug.

I really enjoyed this video as I have one of these 135 watters. I completed the master volume delete and the reverb bypass cap and I am glad I did. Great improvement! Without your video I would have been lost. THANK YOU!!!

@UncleDoug

2 жыл бұрын

You're welcome, Pete.....glad it was helpful.

Am I the only one with CCR in my head when he hits that tremolo channel? 'Midnight Special' just kept coming.

@ZacCostilla

5 жыл бұрын

I thought the same thing

@elymolloy8333

4 жыл бұрын

lol me too

@davidr.g.9118

3 жыл бұрын

Of course

Love your videos, learned more in a few of your videos than I have in years. Thanks Uncle Doug!!

Thanks again Uncle Doug! Constantly learning and enjoying that process.

@UncleDoug

4 жыл бұрын

It's our pleasure, U.

You are my favorite channel on this subject. Thank you for excellent quality content Uncle Doug :)

@UncleDoug

5 жыл бұрын

You're welcome, RL. That's always nice to hear :)

A new video from Uncle Doug = happiness!

@UncleDoug

5 жыл бұрын

I hope you enjoy it, Riccardo.

Uncle Doug has a brain like a super computer. He not only knows his amps, but he's a hot rodder too. Nice car Uncle Doug.

@UncleDoug

2 жыл бұрын

You are too kind, John ;) Thanks !!

Fabulous amp and repairs, and thanks for the priceless information and instruction. Super sweet cab as well!

@UncleDoug

5 жыл бұрын

Thanks, BT.

A giant schematic. You could use this for wallpaper - love it Uncle Doug

Interesting, both the repairs and the mods.

Great these old amps. Nice that they be repaired correctly. Enjoyed the fact you upgraded it as well. Killer Amp! Thanks for video.

@UncleDoug

4 жыл бұрын

You're welcome, Adam. Thanks !!

Mr . Uncle Doug when after 12 yrs. of reading tube amp books, electronic books I went down to guitar center ( the old cheap G.C .) An got one of these, it had beach sand an sea shells in it , homemade backpanels anyway..... That's the one l made all the mistakes went back an fixed l learned everything literally from that 135 watt ultra- linear twin reverb I had that head in there and I swear about 100 times! I love that amp now . Pretty much back to the old Twin rev. Design except .. l did keep that Big Ass power tranny I like 500 volts on the plates, turned the hum balance into a rear accessible Bias pot, got 4 R.C.A. 6L6GC's in there too it's Killer!!!

@UncleDoug

Жыл бұрын

Thanks for sharing with us, Gary. Continued happy coexistence with your Fender Twin.

Thanks for doing a video on the mighty Twin Reverb, I've never owned one but still like the classic sound of a good "Twin"

@UncleDoug

5 жыл бұрын

You're welcome, Gary.

Variable NFB control and reverb upgrade are genius, what a huge improvement! NFB is like having a on amp compressor...really cool.

@UncleDoug

5 жыл бұрын

I'm glad you liked the modifications, S.

@bryanfreisinger2304

5 жыл бұрын

@@UncleDoug I had my 1980 TR returned to BF glory, but unfortunately the new black faceplate covers the MV hole. That NFB pot addition is brilliant!

beautiful sounding amp on my side ... great work as always Sr.

@UncleDoug

5 жыл бұрын

Thanks so much, TT.

Accurate title. :)) Always nice to watch a skilled craftsman at work, thank you. The NFB really cleans it up. The car is looking and sounding good!

@UncleDoug

5 жыл бұрын

Thanks, Andrew :)

Great amp, better tutorial AND a neat ending? You are spoiling us =D

@UncleDoug

5 жыл бұрын

Thanks, Daniel. We are trying to please :)

you're a miracle worker Uncle Doug

@UncleDoug

5 жыл бұрын

Thanks, Mr. P :)

So happy to see you're back Uncle Doug! You're still the best!

@UncleDoug

5 жыл бұрын

Thanks, Thomas :)

Best amp/speaker tone I’ve heard from one of your projects yet Uncle Doug. Well done!

@UncleDoug

4 жыл бұрын

Thanks so much, WW.

I learned the boost trick by experimentation when I was 8 years old. I just unplugged the two reverb cables form the tank and connected their center pins. Instant overdrive. The reverb knob now acts as a gain knob. I still have that old Supro Sportsman...

Been a while.. Glad you're back... Now I'll watch the show... 😁👍

@UncleDoug

5 жыл бұрын

Thanks, James. I hope you enjoy it.

@jutukka

5 жыл бұрын

Exactly so !!!!!

A gold mine for DIYers! Thank you 😊

@UncleDoug

4 жыл бұрын

You're welcome, Damian :)

Thank you Uncle Dough! I've been lerning a lot in this channel. It's amazing how easy it seems to be when you explain how circuits works. God bless you for shearing Greetings from Brazil!

@UncleDoug

3 жыл бұрын

You're quite welcome, Marcus. Thanks for your very nice comments :)

That amp was nice,but your Hot Rod looks and sounds excellent.Nice improvements on her.🎸👍🔌

@UncleDoug

5 жыл бұрын

Thanks twice, Bob :)

I especially loved watching this video as I bought one of these used ('78 best I can tell) from a guy back in 1982. Say what you want about them but I just cranked it up after watching the vid and with the master at 10 (not pulled, very bad the pull) and every thing else dialed into player's discretion it still sounds warm and loud and clean and its an ideal platform for pedals. It does weigh a mother-ton and a half though so it never leaves the house anymore. I have so far been resistant to altering the circuit it but these little tweaks might be just my speed as they could easily and quickly be returned to spec. Thanks again for another great vid!

@UncleDoug

5 жыл бұрын

You're welcome, Keven.

Appreciate your "Hands-On" demo. Was nice to see you demonstrate the controls live.

@UncleDoug

3 жыл бұрын

Glad it was helpful, Paul.

Thanks so much Uncle Doug. I am learning so much from you. You remind me of my instructor when I was learning auto elec many moons ago. Carried out this mod on my friends 78 Showman while doing repairs on it, well done Doug. Keep up the great work and lessons you do Trev

@UncleDoug

3 жыл бұрын

You're welcome, WT. I'm glad the videos have been helpful.

Oh course it hummed. It was too stoned to remember the words...

@ALTDOK667

5 жыл бұрын

Literally, LOL!

@monkeyboy4746

5 жыл бұрын

It's been passed around too much.

@bobsaturday4273

4 жыл бұрын

ARRRRGWAHAHAHAHABWAHAHAHAHA !!!!

@rickwahrlich6259

4 жыл бұрын

You are brilliant! Thanks.

@daleburrell6273

4 жыл бұрын

YOU BETCHER LIFESAVERS!!

Props to you Uncle! I’ve got two of these (one with MV removed) I’m really blown away by how many other people have one too. I recently did half power mods to both and it makes them more usable (and perfect as pedal platforms) As long as you stay on top of your power cap maintenance this amp will not die (I’ve had #1 for 30 years) Super Linear Nation!

@UncleDoug

5 жыл бұрын

Thanks for the input, RT.

I was beginning to worry that you were unwell...great to see & hear you again.

@UncleDoug

5 жыл бұрын

Thanks, Ray. Despite psychiatric diagnoses to the contrary, I am alive and quite well :)

Learned so much from another of your great videos, Uncle Doug. Thanks mate!

@UncleDoug

5 жыл бұрын

You're welcome, Vinny :)

Great job on this video Uncle Doug. As an engineer and guitar player I was very appreciative of your attention to details and troubleshooting method.

@UncleDoug

4 жыл бұрын

Thanks, Steven :)

I have this same amp Uncle D, only from the 60's, mine don't have the push pull master and been wrenched on several times and yes very loud amp! wicked amps when cranked. good video mang!

@UncleDoug

5 жыл бұрын

Thanks, Randy :)

I never thought for a second that you wouldn't turn this wreck of an amp into a functioning masterpiece! Bravo, well done!

@UncleDoug

5 жыл бұрын

Thanks for the confidence, Paul :)

I’m brand new to this channel. Thank you UncleDoug. I know nothing of capacitors, resisters and schematics, but I thoroughly enjoyed watching an obvious master at work. I’ll be watching the archived videos and look forward to new ones.

@UncleDoug

5 жыл бұрын

Welcome, Fuzzy. Keep watching and you will learn a lot.

1 dislike? Probably from the "tech" that "repaired" it previously LOL

@UncleDoug

5 жыл бұрын

Either that or they let some Bellevue psych patients loose in the computer room again :)

@brd400

4 жыл бұрын

popeye What kind of Tech would install those shitty pots, and then wire them wrong?

@MrBuggmann

4 жыл бұрын

@@UncleDoug Maybe some meth head shredder in a hurry to "fix" it. Are you trying to give psych patients a bad name?

@UncleDoug

4 жыл бұрын

@@MrBuggmann Nope. Some of my favorite people are psych patients, Mr. B ;)

I have one of these 1970s Silverface Twins. I do not use it for gigs and have not since the 1990s. Far too heavy to carry around. It does sound great though!

Wow...super nice work. For me the teaching is the best part. I've learned a lot with each of the vids. No one does it better IMHO.

@UncleDoug

5 жыл бұрын

Thanks so much, ID :)

Thank you for sharing and preserving your invaluable knowledge for everyone to use!

@UncleDoug

Жыл бұрын

It was a pleasure, Josh :)

I have that same '78 silver face, modified by Dan Torres himself sometime in the 90's I believe. It was handed down to my brother and I from my father. Thing is fucking LOUD.

That transformer is the same size that powers our subdivision ... Lol ... Good vid as usual . Much appreciated and enjoyed ...

@UncleDoug

5 жыл бұрын

Thanks, Eddy. Dr. Frankenstein could have used one :)

@comicblueswithjonygitar36

5 жыл бұрын

Ultralinear, my back can't take moving this one anymore

@sparkyguitar0058

5 жыл бұрын

I have both a Fender pro tube twin and a Boogie S O B. The transformers in the Boogie are huge compared to the Twin. Even with 2 12's the Twin is just about 5 lbs heavier than the Boogie.

I know jack about this stuff but for some reason Love watching you and also Brad, going over amps. Really enjoyable. Thanks.

@UncleDoug

5 жыл бұрын

You're welcome, SB.

a true magician at work is always a pleasure to watch. thanx UD.

@UncleDoug

5 жыл бұрын

You're welcome, Paul. Thanks !!!

I repair at least 30 of these amps a month. Most customers want them Blackfaced. (Rewire it to 1960's schematic) But the one thing I do on all of them now is to Blackface the bias circuit. Makes the balance pot back onto a true bias pot. Just a suggestion. Also if you ever need tubes or parts I stock everything and have over 4000 tubes. Thank you for your videos. Kevin Tube Tek Chicago

@UncleDoug

5 жыл бұрын

You're welcome, Kevin. I will keep your offer in mind.

@comicblueswithjonygitar36

5 жыл бұрын

Kevin, i have many tube amps, always looking for good tubes, especially 12at7's, true 7025's? Military grade 12ax7, how you set for 7025's?

@kevin2960

5 жыл бұрын

I do. Not sure what at this moment. I just sold a sealed 5 JAN 5751 tubes. I have some Mullard and Amperex including a 7025 labeled Mullard. I have several RCA 7025 but they are not new. They test very strong. I have bins full of NOS and used 12at7 and 12au7. Have a lot of 12az7, 12av7 and 12dw7 also.

@comicblueswithjonygitar36

5 жыл бұрын

@@kevin2960 i tube my amps for guitar, so i need AT7 for phase inverter and reverb stages, and 7025 for most other stages, the Jan 12AT7 is best store bought reverb ones I've found for matching original sound, those groove tube 12at7's are horrible IMO, too noisy for reverb. Phase inverter less sensitive i think, I have DLR, VBR and Twin all need retubing, and a Victoria Regal 2,also needs same compliment. And Peavy DB needs good 12ax7's. Many times the stuff i order is microphonic out of the box, frustrating

@kevin2960

5 жыл бұрын

I quick test on a BK707 and then test everything on a hickok 533a. Preamp tubes I tried to test in an amp also for microphonic noose. Power tubes I can match on a maxi matcher

The name is ultralinear, Jerry Garcia cherished this model. Again for the test you need the jointed pine cabinet and TWO orange JBL special design for Fender speakers, lush reverb and vibrato on about 5 all around master cranked, volume at about 5, sound fills the canyon, this is a Day on the Green 70's Bill Graham gig Twin. I knew a guy who played with Maria Muldaur band in mid 70's, used 2 of these Fenders, trick, in volume 1 out of 2 into 1 of the second amp, that's a big big sound! Again guitar in 1, line out 2 into 1 of the second amp

@goodun2974

5 жыл бұрын

Comic Blues with Jonygitar, Maria Muldaur! A terrific singer, I saw her sing a couple of times back in the day. Free concert in a local park around 1979 or 80, probably had 10,000 people there. A few years later, I saw her in a small club a few minutes walk away from that park, I don't think there were more than 30 people in the audience. Which only goes to show how fickle music audiences are. I also saw her at the Edmonton Music Festival in 1992 (Csnada) along with about 60 other performers on 5 stages. Her ex husband Geoff was playing elsewhere at the festival. Man, she can sing; she was HOT, in more ways than one! She was quoted in an interview once as saying " I'll still want to be a singer even when I'm not so hot to look at anymore." Who was your guitarist friend from her band? And on the subject of guitarists in bands supporting female singers, when I saw Lucinda Williams, guitarist Gurf Morlix was using a pair of blackface Twin Reverbs....

I love the way the current limiter would just start to glow as you played. Great video Uncle Doug.

@UncleDoug

5 жыл бұрын

Thanks, Bill. It's an excellent indication of the increase in current flow to (and through) the amp when it is driven by an input signal.

A spectacular performance by Jack and Ollie! And what an academy award-winning finish! Who knows what is next?

@UncleDoug

4 жыл бұрын

Indeed, Sting, so stay tuned..........................................................

Man that amp sounds good ,nice playing there really enjoyed it your the best,ha ha ha nice ratrod love it

@UncleDoug

5 жыл бұрын

Thanks, Joe :)

Great Mods Uncle Doug..!! I will do that to my 1979 Fender Twin...these twins always sound better with JBL D120F speakers

@UncleDoug

5 жыл бұрын

Everyone says that, Mr. G. It must be true. Thanks !!!

Thanks for another great video and all of your hard work troubleshooting this amp. Thanks for sharing.

@UncleDoug

5 жыл бұрын

You're quite welcome, LL.

So happy you had a Twin on the channel, UD! What a great amp. Twins are not just for the ears. They are truly a visceral experience. I used to argue with my band about the volume when I got above 2.

@UncleDoug

5 жыл бұрын

I share your enthusiasm for the big Twin, TOFO. When they are working properly, they are glorious. When they aren't.....they are a handful to fix.

Great video. I have personally rebuilt two of these in the past. They are great platforms for turning into blackface Twin Reverbs. What was not mentioned was that the output transformer has ultralinear taps connected to the screens and the power supply has no choke. It has been said that Fender(CBS) did this to make the amps cleaner. It did not sit well with players as they sounded somewhat sterile compared to blackface Twins. I like that mod where you add the presence control although I would have used a 5k-l pot instead. Thanks again for another great Fender repair project.

@UncleDoug

5 жыл бұрын

In all the excitement I forgot to mention the ultralinear screen taps, Arnold. I too would have preferred a lower-value pot, but it was all I had on hand.

@goodun2974

5 жыл бұрын

Arnold Shaner , the Super Twins made more sense for pedal-steel players, most of whom play ultraclean*, than for regular guitarists. Actually, I came across a Super Twin at a huge outdoor antiques show some 20 years, which had 3 or 4 piezo tweeters mounted into the baffle above the speakers (holes had been drilled for the tweeters). As I recall, the seller wanted something like 600 bucks for it. Thanks but no thanks! Antique dealers rarely sell musical gear at a reasonable price....although, around that same time, I bought a doubleneck Supro lap steel and a screaming little Valco built Airline amp with field coil speaker from an antiques dealer for $225.... *This attitude or aesthetic might be changing somewhat now that you have folks like Robert Randolph tearing it up on screaming pedal steel....

I love my Twins !

They been around a long time, and I suspect they will be around for quite awhile more ! Just a great sounding amp ! TY for this great video ! 😁✌

@UncleDoug

4 жыл бұрын

You're welcome, Michael :)

Way back in the day I had a Twin Reverb as well. Always enjoyed what that amp could do. Really interesting to watch as you rehabbed that beastie. Thanks for the fun viewing.

@UncleDoug

5 жыл бұрын

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

When I went to GIT in 1984 I used to hit up the local Hollywood music stores for old amps (vintage,what's that??) to learn repair and mod. One day I scored for $75, 3 FENDER AMP CHASSIS''. A 62' BROWN FACE BASSMAN, 65' BLACK FACE BASSMAN, and a 74' SILVER FACE TWIN REVERB. ALL WERE BONE STOCK, but the Twin had a single transistor input buffer added, and a Master Volume. I repaired all three without much difficulty. (Scroll down and read the ******* paragraph 1st...or just wait) I DISAGREE WITH YOU ON MASTER VOLUME ADDITIONS, ESPECIALLY ON 4-EL34/ 6-EL34, 4-6550,and AMPEG V4 amps. A SIMPLE 100% NON-DEFACING, easily reversible (on hand wired amps) PHASE INVERTER MASTER VOLUME Consists of 3 parts! 2 capacitors mounted on a duel pot! THE DUEL POT (mounted in an EXISTING HOLE, [DI, AUX SPKR] ON REAR OF AMP), 2 CAPACITORS (MOUNTED ON THAT DUEL POT), and you are only desoldering one end of each of two phase inverter caps (secure, duh). Two wires from those 2 caps to the pot, and two wires back. THAT'S IT! CRANKING THE MV PUTS CIRCUIT BACK TO STOCK. HERE IS A MORE THOROUGH, REAL LIFE EXPERIENCE BLURB ON MASTER VOLUMES. NOTE, I prefer no mods on Fender amps, but a MV is easily 100% reversible on hand wired eyelet boards. 50 watt or less amps I prefer "ONE WIRE" (one resistor) CASCADED CHANNELS. It was a 5 minute professional quality mod on my 50 Watt Sound City head. I hate FENDER CASCADED PREAMPS (aka Mesa Boogie Mk I "Santana amps". That said, read on and ALWAYS FOLLOW TUBE AMP SAFETY PRECAUTIONS. ------------- I have the 100% tube, 1973 DALLAS ARBITER (manf's of the Fuzz Face)Sound City 120R amp head. A MUST is the simple 3 part, non invasive POST PHASE INVERTER MASTER VOLUME, robrobinette *DOT* com/The_Trainwreck_Pages.htm Just put the knob on the back in place of LINE OUT if you don't want to drill a hole back there. In a twist of amazing luck the 1982 issue of Guitar Player Magazine's HOW-TO *PHASE* *INVERTER* *MASTER* *VOLUME* article came out the exact same week I bought my Sound City 120R! Immediately installed it. It opened up a world of distortion the amp is damn near incapable of with those HUGE Partridge Mains and Output transformers, and with 6-EL34's! I'm telling you, DO IT, you will be in 7th heaven with that beast. 😊 *******Opening MV knob puts the amp back to stock, but why, the SC amp's sweet spot is like 3/4 MV if you want it loud with picking dynamics clean-to-power chord bliss. Saves power tubes and speakers. ATTENUATORS ARE SO OVERRATED! UNLESS YOU WANT TO SOUND LIKE SANTANA, TOM SCHOLZ, or BRIAN MAY, why do you want to squash your entire impedance dynamics? A great amp sound is the interplay between the preamp, power amp, and speakers. For the life of me I can't find that simple simple GUITAR PLAYER MAGAZINE, MASTER VOLUME ARTICLE online anywhere. It is the same circuit that is in the Train Wreck manual. Just google: robrobinette *DOT* com/The_Trainwreck_Pages.htm I had a 50 WATT SOUND CITY head and it sounded great with a simple 1 wire, resistor jumper from channel 1's preamp tube's output into channel 2's input (grid on tube). And yeah yeah consult Groove Tubes manual, that whole ball of cotton.

@comicblueswithjonygitar36

5 жыл бұрын

I bet we know each other, i was in Hollywood 1984,all my pals were at GIT. Did you play Tuesdays at Central?

Yes about the master vol... even Leo did it with his MM trying to give overdrive at lower vol I guess...

This channel is a candy store. Thank You, Uncle Doug

@UncleDoug

5 жыл бұрын

You're welcome, Rick.

GREAT Job! You're amazing! Your videos are really helpful for me as being an amp Tech. Always have some trouble repairing these Vintage American amps... :) Thank you.👍🏻

@UncleDoug

2 жыл бұрын

Glad you enjoyed it, Walt.

I love the ultra linear twins and the 100 watt mv versions as well. I have really dirty pedals, and the twins laugh at them. Marshall's tend to fart out with my pedal rig. My slp 1957 heads don't but they are more like a bassman than later Marshall circuits.

Giant schematics of historic circuits for wallpaper...hmmm...yes, please 😊

@UncleDoug

5 жыл бұрын

I agree, GB, we need to patent the concept.

@tubical71

5 жыл бұрын

@@UncleDoug hmm i have done this when i repaired/restored the Graetz 177and the Saba Freiburg Automatic 3D and put it on the wall next to me, for easier workflow and to put some notes easily into ;)

Uncle Doug is the coolest. I love these videos! I really dug the short “Interstate Love Song” jam. Good taste. Great instruction. Thanks for another great video, sir!

@UncleDoug

3 жыл бұрын

You're quite welcome. JM. Thanks !!

This one sounds really soo well, Bravo Uncle Doug !

@UncleDoug

6 ай бұрын

Thanks. Glad you liked it, Sylvain.

"I can't see jack." Something I say every time I try to find a particular component when I'm looking at a new (to me) schematic. :-)

@UncleDoug

5 жыл бұрын

Jack has copyrights on all use of his name, so send $10 every time you say it :)

@kenhanson4015

4 жыл бұрын

@@UncleDoug I laughed so hard that I snorted.

@UncleDoug

4 жыл бұрын

@@kenhanson4015 Good to hear, Ken. I guess that's the only legal snorting we've got left.

You should frame and hang that schematic in the ol’ man cave Uncle D!

@UncleDoug

5 жыл бұрын

I've marked it all up, but it's still a beauty, Whipp. Maybe I'll do that :)

Thank you for posting, Uncle Doug.

@UncleDoug

5 жыл бұрын

You're welcome, Buzza.

I hope you are still around when I need my toys worked on! You are one smart man and a great technician. Thank you very much UD!

@UncleDoug

11 ай бұрын

Thanks so much :) I hope so too.

I’d advise against removing the master volume. Just set it to 10 and it’s out of the circuit. I usually set the MV on my ‘74 Twin Reverb to between 6 and 8, as it allows my to set the preamp volume higher and tames the amp a bit. The pull boost is useless but it’s totally out of the circuit when pushed in, so does no harm. I’ve considered repurposing the switch, maybe to increase the negative feedback resistor value. I don’t need to continuously vary negative feedback. I left the bias balance pot in place, but added a trim pot in series with it, which allows me to adjust both. For those that don’t know, 135 watt Twin Reverbs used an ultralinear output circuit with additional taps in the primary of the output transformer connected to the screens of the output tubes. I think it provides additional negative feedback to keep the amp clean at higher power. The output stage voltages are also much higher. My ‘74 is the 100 watt circuit, which is way more power than I need these days. It sounds yummy though.

@eddgong

5 жыл бұрын

funny i just commented the same thing ,never understood all the negativity and with a master you have the choice of dirtying up the amp even if using outboard gear or preamps like I do , I found with the MV at 10 to be the same as if no master at all was built into the amp

@eddgong

5 жыл бұрын

Your obviously more knowledgeable in electronics than myself wish I were but........having owned 4-5-6 of these beasts over the years using 2 on sage when space allowed ,Ive never owned a twin with the boost switch though . All 100 watts what this amp has always needed though was a op power select switch instead of yanking 2 tubes to get i down to a small club working volumn and still have tone

@lestelie4410

4 жыл бұрын

Leaving the MV circuit in place is not quite the same as removing it all together. There will still be some minor loading of the tone...in theory. Whether you can hear it or not, and whether its worth the time and trouble is up to you. However, I do like the way Uncle Doug put in the variable NFB/Presence control.

A 135 watt Twin??? That sounds like a weapon of mass destruction, lol. Or at least for inducing earthquakes... A while back, Johan Segeborn did a video of him plugged into a cranked Twin. Some sweet sounding overdrive, but even he admitted he may have gotten a bit too ambitious there, lol. He said it was painfully loud! (Coming from a guy who makes videos of cranked Marshall full stacks...)

Now, that's my kind of consideration! SUPER-well-packed, Easy-to-read SUPER SIZED schematic, thorough explanations...! WONDERFUL! Always been a big fan of the Twin Reverb. Uncle Doug, you are the quintessential teacher. (LOVE the drone and the cars, too).

@UncleDoug

5 жыл бұрын

I agree, Dave. The owner of the amp is a real classy guy......which is why I went the extra mile with it.

Thanks so much for a much needed video! Got a 74 basket case TR that I want to do all those mods to. Really like the bias control in place of the MV. Great work/ troubleshooting UD.👍👍

@UncleDoug

4 жыл бұрын

You're quite welcome, TF. Thanks for the nice comments.

We called that one the evil twin.

Turn it up to a "Not so Seismic-Level" .

Awesome video, thanks Uncle Doug.

You have that one cooking,best 13 twin I have ever heard,been at it for over 40 years.THANKS.

@UncleDoug

5 жыл бұрын

Wow.....thanks so much, Frances:)

Looks like you had fun! At the end of the video the current limited was still glowing, is it supposed to do that?

@EdMuse1122

5 жыл бұрын

Yeah, I was wondering about that, too. It was almost mesmerizing!

@UncleDoug

5 жыл бұрын

Yes, the bulb is correct for the lower-wattage amps I generally work on. In this case, it was inadequate for the 135W TR, so it tended to glow brightly when driven.

Who gives the video a thumbs down? Why? 🤦‍♂️

@UncleDoug

5 жыл бұрын

Rumor has it that it's a leper whose nose fell off and hit the "thumbs down" key.

Wow - great modifications and explanations!

@UncleDoug

5 жыл бұрын

Thanks, Bernhard.

Unbelievable job Doug!

@UncleDoug

5 жыл бұрын

Thanks, Mark.

Crap... I don't have a beer :/ gotta pause the video :D

@klontart

5 жыл бұрын

Hurry up man, we’re waiting ;)

I would turn the master volume to 10 and use the preamp volume for volume control.

@Turboy65

4 жыл бұрын

That's not the best way to get good tone from this type of amp. A Twin doesn't sound its best until the volume control is at 3 at the very least. With the master at 10 that's just deafening.

STP! Awesome :D Nice work on the Fender. I like your attention to detail when you explain why and how you are going to do something to a piece of gear. Love that car too. Neat idea for the sign-off.

@UncleDoug

5 жыл бұрын

Thanks !! Glad you liked it, SS.

Thanks for the Video. I bought my 1968 Twin Reverb amp in the mid 70s and it still sounds like it did 40+ years ago.

@UncleDoug

2 жыл бұрын

You're welcome, QP. I hope it continues to serve you well.

Delivered by Emerson, lake ,and palmer I see !!!.

@UncleDoug

5 жыл бұрын

Yep :)

Those 1970 Fender amps have horrendous wiring and lead dressing compared to the 1960 versions.

@RocknJazzer

4 жыл бұрын

@@Carlosant - no, because most fender assemblers were women, mexican women, even back in the 50s

Awesome work as always UD, thanks for sharing!

@UncleDoug

5 жыл бұрын

Thanks. You're welcome, Shy.

Brilliant work Doug. Thanks for saving another one from the landfill. Finding knowledgeable service techs is a true rarity today and your videos are most enjoyable and informative. I bought a 1969 Pro Reverb about 20 years ago and it used to drop out with regularity when it heated up. After several visits to the local tech, he finally re-soldered the entire board and it appears a loose ground was the problem. Details. Details. Yes, these things ain't light! But they sure sound sweet when kept in original shape.

@UncleDoug

5 жыл бұрын

Yep, the little things can really get you down :) Thanks so much for your very nice comments.

I think ditching the boost was great...but I would have kept and converted the MV to a post phase inverter MV

@UncleDoug

5 жыл бұрын

Thanks for your input, Dave.

@JulianA-tr6pt

5 жыл бұрын

This, 100%. Or even pre-phase inverter, like a regular voltage divider volume control. Master volumes rarely make an amp sound bad unless they are some weird design. Turn it up to 10, and it's virtually out of the circuit. But if you own one of these beasts, you already know what you're getting into as far as clean volume goes. Even a MV won't save you from setting the amp to the infamous .05 on the volume dial...

@williamplatte7318

3 жыл бұрын

@@JulianA-tr6pt Did you replace the MV pot with a different pot? I have a 79 SR with the same mv curcuit, MV is damaged and needs to be replaced. I like the MV, took the push pull out of the circuit. Trying to figure out what value Pot to use and where to put it back in the Circuit, same place or is their a better spot for the mv.

@JulianA-tr6pt

3 жыл бұрын

@@williamplatte7318 ​ I was speaking about my experience with the few amps I've built, which are much lower powered 2xEL84 amps. Personally, I just stuck the master after the preamp stage & EQ, before the PI. 500K Log, cause that's what the amp originally had before the rebuild. Worked for me since my amp has a cascaded preamp with EQ after the two 12ax7 stages, so it can get some good preamp drive with the master down. On a Fender, which is cleaner for a variety of reasons, I'm not sure what would be the best, but I imagine most MVs would sound good. I haven't experimented much with post-PI master vol, but it definitely can give you more distortion. They can get more complicated, of course, with dual pots and safety resistors.

@williamplatte7318

3 жыл бұрын

@@JulianA-tr6pt I think I am going to put it back in the circuit before the PI. Per the schematic it calls for a 1 meg JT pot. The original push pull pot that came out had the typical three solder joints on the top and one on the bottom of the pot and four solder lugs on the push pull switch. Since i am removing the push pull I was looking for a 1 meg JT pot that would just replace the one that came out. Any ideas on where to find such an item? Antique parts has one, but it only has the three solder lugs on the top and no solder lug on the bottom according to the picture. I went ahead and ordered that pot and see if I can make it work. I will update when I get everything up and running.

Steam powered Harley Davidson motorcycles were made popular in Ohio in the early 80's by the infamous motorcycle gang the "Cleveland steamers" !!!.

@HELLHAMMERHANDHIX

5 жыл бұрын

@Sandpile Sammy ...but you did...so now tell yer friends and spread the word that the gangs getting back together !!!.

@HELLHAMMERHANDHIX

5 жыл бұрын

@Sandpile Sammy ...I see your a cb fanatic...me too...been active since 1980...good to meet yer !!!.

@goodun2974

5 жыл бұрын

Nic White , the original "steam-punks"?

@HELLHAMMERHANDHIX

5 жыл бұрын

@@goodun2974 ...WORD !!!

@UncleDoug

5 жыл бұрын

Greetings, Nic. Thanks for the info :)

Cheers Doug from Au. Thanks for sharing your experience & wisdom. Valuable knowledge that anyone into tubes should read. When buying a car wise people go with what mechanics recommend. When buying amps go with what a veteran tech like you recommends. GOLD!

@UncleDoug

2 жыл бұрын

Thanks so much, GF :)

Love to watch these videos ! You are a master fixing these beautiful machines Sir ! I got a 1978 135 W Fender Twin too and I really like it, i still play live with the old amp and it rocks ! Even though the Vibrato is dead too, Cheers from South América - Bolivia !

@UncleDoug

4 жыл бұрын

Thanks, Ramiro :)