Late-40's Mirovox Guitar Amp.....In for Repairs at Rusty's Workshop

This video features a very uncommon but attractive late-40's Mirovox amp that arrived on our workbench with several issues related to a hair-trigger volume control, inadequate tone control, hot 6V6 tube bias, and an out-of-place, improperly wired output transformer. After showing and testing each repair, we turn the amp over to Ollie & Jack for their traditional audio testing session. As if this were not enough, we do a media search for information on Mirovox amps, open some gifts, and engage in a philosophical discussion regarding the vicissitudes of desert weather.
Our second feature is the Part 2 (and final) installation of an all-new front suspension on a 1930 Model A coupe. At the end, you will see it in all its "glory" ;)
If you enjoy advertising-free videos like this one, please subscribe to our channel and consider becoming a Patreon patron at this link: / uncledougsvintageamps or making a PayPal contribution to: [e-mail]. Thanks so much for watching !!

[@TonyPepers]

Greeting from New Zealand Uncle Doug. I'm Tony Pepers, the inventor of Rocket Sockets. I appreciate the plug. It's pretty crazy how much traction and support these have had all over the world. The original design was simply me looking for a solution to not damage guitar pedal artwork or paint jobs. I searched the web for plastic tooling and struggled to find anything. So I purchased a kitset 3d printer and designed and printed an early version in PLA. They were of course quite a bit far removed from where they are now. They would wear out pretty quickly being of a soft plastic and also the nature of FDM printing not being very strong. When other people started asking if they could buy from me I had a feeling I was onto something. I printed and sold about 150 sets of them. A few years went by and one day I woke up and decided to go see a local plastics manufacturer and have a chat about mass production in a more durable material. I then launched a Kickstarter campaign mid 2019 to help get the tooling made up. I have since shipped out over 2000 sets and demand is still high. I'm extremely happy that a little piece of my kiwi ingenuity is in so many workshops around the world and is making life easier for so many people. Keep making excellent videos!

[@UncleDoug]

What a great success story, Tony. Thanks for sharing it with us. I really like the socket set and have been using it often. Best of luck with your venture !!

[@82abn34]

I'll be ordering a set too Tony. I've got a Kenwood KT-10 (1964 or so) sitting on the bench right now and a set of those plastic sockets will come in handy. The silk screening jumps off the front panel when given a mean look on those things.

[@PetraKann]

Mr Peters appreciates “the plug”. Get it?

[@nigelpickett2471]

Tony, well done, the simplest of ideas are the best.

[@mightyV444]

I'm also in NZ! :-) Bit chilly here at the moment! ;-)

[@williambiddle5683]

Uncle Doug, You sir are what the internet was invented for. Thank you for your wonderful educational contributions! PS R\The car is stunning!!!

[@UncleDoug]

Wow.....thanks twice, William. You made our day :)

[@goodun2974]

Actually, no, Everybody knows the Internet was invented for cats, and Uncle Doug's postings are just an unintended but welcome side benefit.

[@robworrall6832]

Absolutely spot on Sir

[@vintagetubeamplifiers]

I often re-watch all of your videos as you're the best teacher, easy to listen to, thorough, detailed and explain everything in an easy to understand way. I've learned so much from you. Thank you Uncle Doug, my favorite Uncle! 🙂

[@UncleDoug]

That's great to hear, VTA. Best of luck with all your projects.

[@PetraKann]

During this time it’s people like Uncle Doug that reminds me of what I use to like and respect about the USA as a nation of people. Cheers from down under

[@UncleDoug]

Thanks so much, Petra. Please be sure to subscribe.....we need your help to reach our goal.

[@PetraKann]

@@UncleDoug Not sure how long I have been subscribed to your KZbin channel, but I have seen many of your video uploads. I wonder if you are aware of this device from Russia, the Apparatus Duophonic Synthesiser that exploits valve technology. Very stylistic design (although the price is hefty at $1899 - looks great though with 7 valves on the top) Cheers apparatus.su/

[@davidwinokur2131]

Like you, as I get older, I find that the number of times I'm wrong continues to grow. Also, and I asked my wife, the number of times I'm right continues to decrease.

[@UncleDoug]

The two tend to go together, I've noticed.......especially when one asks the wife ;)

[@bradleyleben7785]

Old amps, old hot rods, and no virus! It’s a great day! Good to see ya Doug.

[@UncleDoug]

Life is good once more, Brad :)

[@ibanezleftyclub]

I used to watch Bob Ross when I was a kid on Saturday mornings, now it’s Uncle Doug...

[@UncleDoug]

At your service :)

[@julesl6910]

Bob Ross has nothing on Uncle Doug, a chihuahua to a bloodhound

[@donkimble]

The sublime pleasure of an honest gentleman at work. Even when I have no clue what’s going on beyond “amp make loud”.

[@UncleDoug]

Thanks, Doc.

[@johnbaker5717]

Regarding the 15" speaker in the Mirovox amp found on Reverb. It's obviously a TARDIS (note blue color and call box shape) so of course it's bigger on the inside than on the outside.

[@goodun2974]

John Baker, That TARDIS amplifier can only be disassembled by use of a sonic screwdriver!

[@UncleDoug]

Excellent observation, John. That would explain the glimpse of a bowling alley and golf course that I got from the inside view ;)

[@billdyke9745]

A 70 year old that still goes out to play. (The amp, that is)... Respect.

[@UncleDoug]

Heck, I go too, but only if it doesn't interfere with my nap.

[@tommyfoley]

Great amp repair and tips. Geez Louise, the rat rod has turned out just amazing, UD!!!

[@UncleDoug]

Thanks twice, T :)

[@davidk8893]

that's no rat rod, it's a proper hot rod. An astonishingly nice one as well

[@LitesLAB]

Yes! Now my Saturday is complete!! At least for the next hour, lol

[@UncleDoug]

I hope you enjoy it, LB :)

[@Sibbe2560]

liteabong: couldn’t agree more...👍

[@rmg471]

Yes! New Uncle Doug!

[@butchlauer]

I love the deco lettering on the Mirovox control panel as well as the classy grill cloth. Great job of bringing her into this century.

[@UncleDoug]

Couldn't agree more!

[@elcochipit]

allways an inspiration to see the passion, experience and work of Uncle Doug

[@UncleDoug]

Thanks so much, C.

[@NengYuTu]

great tone and sound, very well and detailed explained

[@UncleDoug]

Thank you kindly!

[@thegusk520]

Very nice and your little tips are the icing on the cake.

[@UncleDoug]

Thanks, Gus. This was a good opportunity to discuss pot value selection.

[@GL64]

Man you do some cool stuff. Keep it up!

[@UncleDoug]

Thanks. Will do :)

[@ronnewby3196]

Another great video ! Thanks for all info Ron

[@UncleDoug]

Glad you enjoyed it, Ron :)

[@keithmccormick1272]

Uncle Doug . Old TV technician here and to me that speaker looks just like ones I would see in console stereos from the 50's . Love your videos , I dont repair anymore but I think I still have cleaning fluid in my veins :)

[@UncleDoug]

Thanks, Keith. Once a tech......always a tech :)

[@bluesman97]

Thanks Uncle Doug.. Great Video as usual.

[@UncleDoug]

Our pleasure, BM.

[@PrinceWesterburg]

I started watching this in the bath but thankfully continued on my PC later - love it when I have to take notes like I'm at a university lecture! Never before has someone explained output transformers 'refelcted impedence' so perfectly. Oh and the hot rod - Thats how ALL cars should look. Simple, classic, elegant. Pure beauty.

[@UncleDoug]

Wow.....thanks so much Prince. We're glad you enjoyed our video :)

[@raymondlau6507]

It's always a good day when I see that a new Uncle Doug video has been posted. The Mirovox amp sounds great, with nice clear treble.

[@UncleDoug]

Thanks, Raymond :)

[@crispysyd9190]

Great job as always. Sweet amp for sure, so clean.

[@UncleDoug]

Thanks, Syd :)

[@davidstuckey102]

Thank for another fine amp job, Doug. Just what I needed today.

[@UncleDoug]

You're very welcome, David.

[@timothyb1559]

Another outstanding video! Thank you, Uncle Doug.

[@UncleDoug]

You're welcome, Tim. Glad you liked it.

[@normanhenderson9290]

What an incredible engineer... your ability to see clearly the problems and solutions is what is missing in our newer generations. Hopefully we can resurrect that ability... Although i also know its inborn.

[@UncleDoug]

Thanks so much, Norman. We really appreciate your kind words.

[@rjprivate]

Thanks for the lesson on transformers sir! Very useful

[@UncleDoug]

You're welcome, RJ.

[@olivercorrodi3340]

always loving your videos. warm greetings from switzerland!

[@UncleDoug]

Thanks, EC. From your screen name, I would have thought Mexico instead of Switzerland ;)

[@thelokifiles]

Informative , thank you Doug.

[@UncleDoug]

That's our goal. Thanks, LF :)

[@beardedjediguitars]

Sounds great uncle Doug!

[@UncleDoug]

Thanks, BJ :)

[@SciPunk215]

Great amp, great sound, great video, great everything.

[@UncleDoug]

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

[@nevillegoddard4966]

Beautiful job Uncle Doug! You fixed every problem your customer had! I'd love to hear what he said; surely he'd be 'over the moon'! I love your unique '30 Ford.

[@UncleDoug]

Thanks twice, Neville. Yes, he was quite pleased :)

[@unclepacky7204]

Great job as always Doug, Luv watching your amp video's !!!

[@UncleDoug]

Thanks, Unc :)

[@Mojoman57]

Thanks, UD. Yet another journey through all things done the right way. I appreciate your effort.

[@UncleDoug]

You're quite welcome, M57 :)

[@davecooper5951]

RIP Jeff Beck. Ace British guitarist and Hot Rod builder.

[@UncleDoug]

Amen, Dave. The guitar world will never be the same without him.

[@markmcmyn8967]

Beautiful sounding amp!

[@UncleDoug]

Thanks, Mark :)

[@rickyboorman3924]

Interesting as always, when I start your videos I can't stop watching👍🏻

[@UncleDoug]

I'm happy to hear that, Ricky :)

[@46bovine]

Another interesting amp video and car video. Thanks Unca Doug!

[@UncleDoug]

My pleasure, Bob :)

[@kolinevans9127]

Nothing like it Fantastic on both the front end and amp. Thanks for sharing

[@UncleDoug]

Our pleasure, Kolin :)

[@markperron4566]

Another awesome video! Thanks for including the output transformer turns ratio refresher. Looking forward to the next video.

[@UncleDoug]

Thanks, Mark.......glad it was helpful :)

[@frogbastard]

As always,a joy to watch your videos.Enjoy the fabulous ride.

[@UncleDoug]

Many thanks!

[@paulhammersley4562]

great to see all the obscure amp's you showcase, plus the tech tip's, thank's Doug,

[@UncleDoug]

Our pleasure, Paul. Thanks for joining us.

[@duanethompson2360]

Very good job explaining the issues and fixing them as always!

[@UncleDoug]

Glad you liked it, Duane :)

[@duanethompson2360]

Uncle Doug just saw you raved about on Blueglow by Mark, a great engineer!

[@jimmyfischbeck9872]

What a little Gem! Nice plating too!

[@UncleDoug]

Thank you 😋

[@AxelWerner]

THANKS for keeping your videos free from ADs!!

[@UncleDoug]

It's our pleasure, Axel. In return, would you please subscribe to our channel ?

[@AxelWerner]

@@UncleDoug i cant . as a long tyme youchoob subscriber of you it just wont let me do it . interwebs broken i guess. Someone deleted it. ^-^

[@UncleDoug]

@@AxelWerner Thanks for trying, Axel.

[@ronnie5129]

Doug, it sounds Great

[@UncleDoug]

Thanks, Cuz :)

[@chazdog789]

Thanks Uncle Doug...

[@UncleDoug]

You're welcome, Charlie :)

[@joemcgraw5529]

Love everthing you did to the amp what a nice 1 ,nice update on the ratrod many thanks again for your very wanted knowlege

[@UncleDoug]

Glad you enjoyed it, Joe. Thanks !!

[@Darryl603]

Beautiful work on both the amp and your ride

[@UncleDoug]

Thanks twice, Darryl.

[@kevinwager9284]

Really nice work and save.

[@UncleDoug]

Thanks, Kevin.

[@MrMeik1970]

Very nice Video Uncle Doug 👌I learned so much from you. 👍

[@UncleDoug]

Thanks !! Glad to hear it, Meik.

[@phillindower8550]

I must come back to this Uncle Doug. Doing errands now. I've learned a lot from your great videos.

[@UncleDoug]

See you later, Phil. That's good to hear.

[@bobross6802]

Thanks for the great vid, Doug !! Amp and Ford turned out excellent :0)

[@UncleDoug]

Thanks, twice, Bob :)

[@janisinisalo]

Those rocket sockets REALLY are a lifesaver, not regretted participating in the kickstarter!

[@SpicyKalabasa]

I've watched all your vids and inspired me to build my first SF1 from a vintage tube radio.

[@UncleDoug]

That's great to hear, Jox. Keep up the good work :)

[@stuartgoldsmith2310]

This is excellent and I particularly appreciated the explanation of reflected impedance. Thanks!

[@UncleDoug]

Glad it was helpful, Stuart.

[@darthbubba866]

In memory of Rusty I am now subbed.

[@UncleDoug]

Thanks, DB :)

[@nickdevriese]

Pure class! That car is excellent! And great job on the amp. Love your videos and have learned a lot! Many thanks.

[@UncleDoug]

Thanks so much, Nick :)

[@jayster.k.wiseguy]

was a Sunday mechanic in Berkeley~ climbing on one's back, get up for tools and get back down there~ was part of the job~ many times per day~

[@UncleDoug]

Sounds tiring but rewarding, in a repetitious way, Jay.

[@Bigjoedo66]

Great Video Uncle Doug, what a master Fabricator you are!!

[@UncleDoug]

Thanks twice, Big Joe :)

[@fixitmyself]

Thank you Doug!

[@UncleDoug]

You're welcome, BN :)

[@mikeroadblock]

Super great vid and good work all around. Good to see you again Doug. It’s always nice to chill with you and watch you work while teaching us. Thank you. Cheers! ✌🏽🎸🏎

[@UncleDoug]

Glad you enjoyed it, Mike. More videos are on the way :)

[@Justafeller]

"Well, originality kinda flew the coop with this one a long time ago." Got that right. Lol.

[@bigjimmedalock4878]

Uncle Doug another great video .I always look forward to next one with great anticipation.And once again ad free, You are the Man !

[@UncleDoug]

Thanks so much, Big Jim :)

[@ringostarr4520]

One of my favorite sounding amps that you have resurrected. Clean & clear all while a bit of grit to add some imperfect perfection. Hats off to you Doug!!

[@UncleDoug]

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

[@samiam5557]

Onkel Doug macht es wieder, großartige Verstärkerreparatur, Sir.

[@UncleDoug]

Vielen Dank, Sam. Wir freuen uns, dass Ihnen unsere Arbeit Spaß macht :)

[@philipthomas8440]

I'm sure the customer is ecstatic with the results of your repairs! You really hit it out of the park on this one. Great work and sweet sounding amp! 2 thumbs way up!

[@UncleDoug]

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

[@dhix2388]

your eye and expertise for details regardless of the task very impressive. always enjoy thanks for your time.

[@UncleDoug]

Thanks, DH. It was our pleasure.

[@thebooda]

Another wonderful Amp & Auto show! You are a pleasure, Sir. Thank you as always for your time and effort and toutalidge!

[@UncleDoug]

My pleasure, Craig. Thanks !!

[@ThePreyMantas]

As usual, great explanations and commentary as well as a troubleshooting, repairs and mods. I like this amps face and sound. It's so cool and rustic looking and works as one would expect it to function during various adjustments. Another great fix in the can! Beautiful custom fabrication and workmanship in the connector and pro install of the discs. I love it and you gotta always take many test drives... ;) What a beauty she is now from what she was... Wow!

[@UncleDoug]

Thanks so much, PM for all your very nice comments and observations :) Have you subscribed to our channel yet ?

[@joereedmusic9853]

Very good run through on this amp. A great improvement from where it was when you got it. You simplified turns ratios and impedance matching for me, stuff that I had forgotten long ago when I use to teach this stuff.

[@UncleDoug]

Thanks so much, Joe. We're glad you enjoyed it. Please subscribe to our channel if you get the chance :)

[@cassvirgillo3395]

Hello Uncle Doug & Family, Ollie and Jack keep your hands free to work the controls. Great repair, I learn a lot in every video, Thank you. Them cat's been practicing. You always do such nice work on the amps and rods. Glad your doing well. All the best, Cass.

[@UncleDoug]

Thanks so much, Cass. It's good to hear from you. YT says you haven't subscribed yet.....are they wrong ?

[@cassvirgillo3395]

Hey Uncle Doug, Yes, they are wrong. I have been a sub for about 8 years, give or take. I clicked the notification bell then. My favorite channel of all. Late Spring but has been like Winter, trying to get nice. Can't wait to see what you do next. Take care, see ya, C.

[@TATEXPRESSINC]

Great job on the video👍🏻

[@UncleDoug]

Thank you! Cheers!

[@charleslambiase5670]

Now when you're playing with your carpicture me my work is working on a big old machinery and getting it alive again especially old diesel stuff, you are the best Uncle Doug!!!!!

[@UncleDoug]

Thanks, Charles :)

[@charleslambiase5670]

@@UncleDoug you are welcome Uncle Doug it's a learning experience the thanks is to you

[@mattdoliver1984]

What a beautiful quaint little amp 👍🏼

[@UncleDoug]

Well said, Matt. It is indeed :)

[@jlore6344]

Cool amp indeed and it looked like a real challenge. Also what a car!! Wow!! Well done!

[@UncleDoug]

Thanks twice, JL :)

[@tomcaneschi4610]

Absolutely gorgeous car oh and the amp is really cool too thx for posting

[@UncleDoug]

Glad you liked them both, Tom.

[@nigelpickett2471]

Greetings from across the pond, I really look forward to your uploads, nice sprinkling of irony and masses of information. Many thanks.

[@UncleDoug]

Thanks, Nigel. We appreciate it :)

[@mackfisher4487]

I’m not a musician and the only time I’ve ever been interested in audio amplifiers used for AM modulated transmitters, but your troubleshooting process is interesting and I picked up a few tips your videos are entertaining thank you.

[@UncleDoug]

Thanks so much, Mack :)

[@mozilla2576]

One of my favorite repairs. I enjoy watching you dissect problems and brainstorm solutions. Very entertaining. Thank You, Sir!!!

[@UncleDoug]

You're welcome, Mo.

[@antoniodimeo]

The control panel is absolutely gorgeous!

[@UncleDoug]

I thought so too, Antonio.......beautiful script.

[@yernickle]

Nice fix / cleanup !

[@UncleDoug]

Thanks 👍

[@bevo65]

"Having the wheel depart from the vehicle." Uncle Doug sure has a way with words. 🤣

[@UncleDoug]

I try to understate the tragic possibilities ;)

[@bevo65]

@@UncleDoug Thereby adhering to all the best engineering traditions.

[@amoruzz]

Wow.. That amp tone was so smooth and relaxing sounding to the chords that you were strumming. That Rola really sounds smooth, just beaitiful. From one old palm bearing packer to another. Great work! Cheers!

[@UncleDoug]

Thanks, Amo :)

[@hpelisr]

Well done awesome Hot Rod, Yes Hack is still watching. On and off at times, love your work.

[@UncleDoug]

Thanks, Hack. We always look forward to hearing from you.

[@jamesunderhill1603]

Cheers UD, good tip on pot values.

[@UncleDoug]

Thanks, Jim :)

[@BadChizzle]

OMG! One of the best sounding amps I’ve heard in a while. This beautiful thing sings! ! ! Not one effect needed... the breakup is... To. Die. For!

[@UncleDoug]

Thanks so much, BC. I hope the owner feels the same way :)

[@BadChizzle]

Uncle Doug Indeed... but... if it retained its overall output level... and can compete in jam situations with like wattage amps, it’s gonna kill for the owner. But, (that being said)... as everyone says now... mic it live! Ha ha ! Sounds sooooo good!!!!!

[@UncleDoug]

@@BadChizzle Thanks so much, BC. It was even better in person :)

[@BadChizzle]

Uncle Doug Sorry about my going on about this one the way I am, but two final things come to mind for your consideration: 1. If you could get relatively small wattage amps say 5-20 or so... and make em sound like this, with this kind of master and preamp volume setup, you may be able to start a big $ side business selling to studios all over this small world. Just marry it with your video process as Demo and a byproduct of non customer repair amp projects. 2. If the power amp overdrives anywhere nearly as sweet as the preamp, file this circuit in your to do list. 3. Ooooops, I went to three! Oh well. If it cleans up when the power section is up high and you creep up on the preamp, everything I said in this thread x10! Ok... I’m done, I promise. 🎙🎛✨

[@cerberus50caldawg]

Beautiful work Uncle Doug. As per usual your tastes in all things are impeccable. Gorgeous work on the amp... That car takes my breath away. You are truly a master sir!

[@UncleDoug]

Thanks so much, CC. You are most kind :)

[@johnb5519]

If anyone was going to sort that one out without a schematic, it was you. Beautiful clean sound out of it too. The master volume pot on my amp was making an awful scratchy sound when it got up to around number three. So I put the ohm meter on it and saw it was going haywire at that range. I took it out and opened it up and noticed some of the resistive material had come off the track and was a mess. I ordered a new one, 100 k, and replaced it, and it works like new again.

[@UncleDoug]

Thanks, John. That sounds like a good repair on your MVC.

[@jraimondi]

Love it👍 what a cool amp

[@LarryDeSilva64]

Really great repair video on that '40's Mirovox amp. A really super nice job on the front suspension of that 1930 model A street rod as well. Thanks for sharing all of your hard work and making it look easy.

[@UncleDoug]

Glad you liked it, Larry. Thanks !!

[@GuitarSmith.]

Gave this one the thumbs up before even watching it. Got to get my repair shop open for Saturday Walk-in service. I'll watch later. Thanks Doug.

[@UncleDoug]

I hope you enjoy it, Martin :)

[@GuitarSmith.]

@@UncleDoug Excellent video as always Doug. Don't know if I've given you this link before mnluthier.com If you have a half hour or so read through Restoring Millring's 1260 and look at the photo gallery of the Harmony's I've restored.

[@anotherOneMore7]

I KNEW there must be a transformer placement commandment from God! I just knew it. That explains a lot.

[@UncleDoug]

Yes, it was commandment number 12, right after number 11: "Thou shalt keep one hand in your pocket when working on live circuits".

[@daleburrell6273]

@@UncleDoug...what number Commandment was: "In parallel circuits, thou shalt not vector for impedance!"(?)

[@andersonrowland]

One of the best channels on KZbin. The amount of knowledge and experience demonstrated in your video's is outstanding! Thank you for your time.

[@UncleDoug]

Wow....thanks so much, 59A (fine truck, by the way) :)

[@jloewenheim]

Another gem!

[@UncleDoug]

Thanks, Jl.

[@johnbravo7542]

The car looks great Doug,well done.

[@UncleDoug]

Thanks, John :)

[@ebswift]

Thanks Uncle Doug, I've been taking a lot on board, it's enjoyable watching your videos, and very educational. I've been working on my Aussie Vadis 600R (about 1965 made in Sydney) for some time, just finished making my bias measuring socket adaptors today, and also today a nice bloke named David Browne in Victoria just completed the rewind of my power transformer which had shorted while with the previous owner. I'm going through it nice and slow, fixing things that need fixing, a lot of time and effort doing something that is an afternoon walk in the park for you. Keep 'em coming and I'll be watching :).

[@UncleDoug]

Your approach makes sense to me, Eb, slow and careful, enjoying every minute of the process. After all, it's a hobby, not a race to the finish ;)

[@georgekrabs6948]

Uncle Doug I've always loved your amp work but your hotrod work is stunning One mean looking machine

[@UncleDoug]

Thank you kindly, George :)

[@johnfritzenjr.1240]

Sounds great 👍

[@UncleDoug]

Thanks, John.