Tube Audio Amplifier Troubleshoot Repair and Modification

[@MrCarlsonsLab]

*HEY! Check out their new Album, this is their KZbin Channel:* kzbin.info/door/RfzHcNCRwDC_dlRGKOUZEw This amplifier is "heavily" used in it: *To purchase their music, and support their band, go here:* itunes.apple.com/ca/album/high-impedance/id1222351741

[@BrokebackBob]

Mr Carlson's Lab You are the GOLD STANDARD for this type of KZbin channel. Period. Mic drop.

[@danielmurray8778]

BobEckert56 I agrees entirely. Extremely informative, dense but not overwhelming, and very entertaining... gets me through those days I can't hit the lab, Mr Carlson keep up the great work!!!

[@endrestory4345]

Nice video. Im hapy here from Norway. Thanks

[@planker]

Not sure how to use “reply”

[@woodywoodlstein9519]

Someday I hope to understand all this stuff you are talking about. So extensive. So in depth and thorough.

[@bwithrow011]

Dr. Carlson is amazing. The knowledge he has amassed qualifies him for an honorary doctorate

[@thomaspartin8968]

Completely agree! Wish that were how it works! lol

[@Jeo-fq1zw]

He teaches the masters

[@RussMcClay]

I'm a child of the 50's and my dad was a radio technician among other things. Our funky, detached wood garage was his lab and it was filled with oscilloscopes on shelves just like your lab, Carlson. Dad's long gone, but your videos have brought a big part of that back to me. I am overwhelmed at your knowledge and expertise and your very clear explanations. Thank you.

[@Wassenhoven420]

How does one keep equipment like this stored in a detached building with no heating / humidity control? Do you have any tips, or is your local particularly favoring to this type of thing?

[@floorpizza8074]

I am just awestruck by your attention to detail... right down to the added jack; handmade, hand painted, and stamped. Looks exactly period correct. You'd never know that it wasn't a factory original part! I just didn't think such workmanship and care existed in today's world. And don't get me started on your capacitor bank! Every. single. detail... perfect. Those soldering joints!!!! I've been soldering for 40 years, and thought I was a dab hand. Yet I could never make such consistently gorgeous joints! Mr. Carlson, your work is just jaw dropping. I really hope that someday you'll take on an apprentice to pass your skills on to another generation.

[@BruceNitroxpro]

This is a "repair" which strains the definition of "repair!" It is the application of modern theory and common sense to a lovely old amp which had seen hard times. It will now be the centerpiece of a modern group in a different world... and will represent its age extremely well. Hats of to Paul again on an excellent set of values applied to a difficult job.

[@robertyuille3774]

1959 1962 I took electronics at George Westinghouse Voca Tech HS Brooklyn NY--We studied Theory and built an vacuum tube Volt meter, vacumm tube HiFi AMP, AM/FM radio, troubleshoot and repaired TV s------Teacher name Mr . Wellman You did more instructions on theory and troubleshooting in this session than I was able to learn in those 3 lovable years. I Love you man ---Budweiser for you.

[@TY-ob7fz]

Hi Robert. I'm an alumni of same high school 5 years later. The teachings there took me though a life of seeing and not fearing circuitry in it's mixed forms and through playing with automotive electronics as well as computers. Bless those teachers sharing their knowledge and their tolerance to teenage pranksters. And Mr. P Carlson of your invaluable knowledge, many thanks !!

[@jamesfenton7338]

It's refreshing to see a true master at work, it's very rare in this world these days.

[@pda49184]

I've just watched this presentation for the second time, (two years later) , and I'm still in ore of your skill, knowledge and artistry Paul.. At least this time round I had a better understanding of your methods and analytic style. I know I'll never be in the electronic comfort zone that you have found, but your example will inspire perfection in the next generation of electronic engineers.

[@bparker86]

One of the smartest guys in KZbin hands down. And without a doubt my favorite person to watch diagnose radios and amplifiers. Sheer brilliance

While a ground floor education in Electronics is always great..for those (like myself) that don't have a formal education and am going in a 'round-about' way to learn @1:55 .... your method is the most valuable I have found and you're the person I promote to young people I know. A major bonus is you're not trying to 'appeal' to anyone with pop culture garbage wedged in to 'keep attention' spans. This amplifer was a real rare gem to see thanks so much. Human invention is quite the impressive thing when it's a true open market.

[@MrCarlsonsLab]

Thanks for your kind comment!

[@towerman75]

Another good video. I'm a retired Electronic Design Eng., and at 75 years of age, guess what, I'm still learning. Great work...

[@drivanivan]

Well i don"t need anything fixed 'yet'...lol.. but i wanted to compliment you on these projects..I am not only impressed, but I'm amazed at your knowledge base on all this work... I'm only an electronics enthusiast but I love listening to your explanations, diagnoses..and repairs on these jobs... and honestly I'm even amazed that you know everything that you do because you look so young to have such an excellent command of the educational teachings and video production aspects of everything on your channel ....not to mention your organizational skills of everything . ... I've had much fun here and look forward to more videos from you ...Great job..thank you

[@MrCarlsonsLab]

Glad your enjoying the video's, and thanks for the kind comment!

[@abeleballestri612]

Mr Carlson's Lab it was a little difficult for me to follow because sometimes you speak very quickly for me as a foreign language. I enjoyed it a lor, anyway

[@BruceNitroxpro]

@@MrCarlsonsLab , As a teacher, I must say you speak well... except for the things which almost everyone slips on... the "dead" use of adverbs. The "ly" is left off of almost everything these days. Also, a few extra words are added which don't make things any more clear. All in all, your grade of A+ is well deserved!

[@greggaieck4808]

Mr Carlson the tube amplifier from the 30s is cool

[@SwingingChoke]

I'm a young EE, I am a tube enthusiast and I must say I you have taught me some of the most professional work habits I now use day to day.

[@oskar3428]

What an impressive perfectionism combined with explanations which are state of the art even for laymen like me! I'm mainly interested in boatbuilding but your channel Mr Carlson is an outright enrichment for the whole YT community.

[@MrCarlsonsLab]

Thank You for your kind comment Oskar!

[@rty1955]

Impeccable Paul. I do the exact same thing before applying ANY power. On the machine I work with (2" quad video tape machine) I usually unplug the various power supplies, pull ALL the Modules from the machine. Video head assembly and remove anything I can remove! I Make inventory of all circuit cards and label them with paper tags amd carefully place them in a special box. I get my air compressor and blow out years of old tape oxide, tobacco ashes and other misc dirt. I then begin all the bench work, checking/replacing caps. I made a jig to bench check the various power supplies. Once they are operational. I check the wiring harness, and backplane for any PS issues. And ok and on it goes. It takes months to restore son I can afford to be meticulous like you. I am so glad to see a person who also slows down, take time and safely!!

[@rexroman5211]

It is fascinating to see you work. Everything makes sense. Why is there only one of you out there?! Thanks so much for enlightening us all,

[@gasser1ify]

I know absolutely nothing about Electronics especially engineer electronics and I am hooked to this channel you are fantastic

[@hendrikhendrikson2941]

Your skills are beyond planet Earth ! Thank you for such an in depth video.

[@MrCarlsonsLab]

+Hendrik Hendrikson Thanks for the kind words Hendrik!

[@torreslarry6837]

@@MrCarlsonsLab they"re right"' now how"bout building a ribbon tube mic,, i"m only kiddin" Thanks,,

[@darkgreenambulance]

​@@torreslarry6837 Not at all - Good idea! " Many a true word spoken in jest!"

[@sincerelyyours7538]

I wish I could give more 'thumbs ups' for this video! What a trove of information Paul gives about tube amplifier design and implementation as it was done in this wonderful old late 1930s Thordarson T20W40 amplifier. He then goes through a step-by-step modification process to bring it up to modern reliability standards so the the owner can take it on the road knowing that it will perform perfectly every time he uses it -- all that without damaging its look, function or old-time esthetics. This is the third time I viewed the entire two hour long video and each time I learned so much more that I didn't quite pick up on or understand before. Paul really packs in the electronics knowledge here and you can't get it anywhere else.

[@davemckim6236]

Wow great video! That old amp probably sounds better now than the day it left the factory. The protection circuit that you designed and built is a real stroke of genius. Your care and attention to every little detail is very impressive and not likely to be equalled by others. Great job!!

[@MrCarlsonsLab]

+Dave Mckim Thanks for the kind words Dave!

[@karlfell3768]

from beginning to the end the pace and content is totally absorbing. I personally have no interest in audio equipment but that did nothing to spoil my enjoyment of the video. I love your attention to details that most would never even consider. keep up the fantastic work and looking forward to many more videos in the future.. Karl

[@MrCarlsonsLab]

+Karl Fell Thanks for the kind word Karl! Many more video's to come :^)

[@gamhazell]

+Karl Fell Bro. That is exactly what I was thinking. I understand very little of what is being said but I couldn't stop watching. Haha

[@c.brionkidder9232]

Agreed. I was captivated the entire two hours!

[@alsamadsheikh3301]

00

[@markbatten5178]

Another great repair video!! And this time you scared me a little when you "rebuked" the amplifier! I noticed it quit throwing surprises right away. Perhaps you could start all repairs with a finger wag and rebuke. Thanks again for the excellent and thorough repair and circuit protection device.

[@JessicaFEREM]

your videos never age. I honestly thought this video was from the last few months, but it's back in 2015. that's crazy.

[@billygo6135]

This is what makes an engineer an artist !!!

[@nickwashburn723]

I would love to see you give it back to the customer. If somebody went above and beyond on a machine of mine like you always do, I would be in tears.

[@MrCarlsonsLab]

Thanks Nicholas!

[@williamhayden7711]

Mr. Carlson, what a fantastic video. Start to finish. It had everything. If there are people that want to learn electronics this is the channel they need to be watching. Also this video really helped me understand what you do for a living. Your website does a good job of that as well, but this is like having a window into your workshop and getting a guided tour. It's a real treat. Keep up the great work! I'm floored. Also you do fantastic work! Beautiful what you did here. I can't imagine your time and services are inexpensive, but I would say you are worth every cent and in reality are probably a steal. You go the extra mile and that's not a common thing. Now I'm like, "what video do I watch next?" Caps in backwards, FT-1000MP repair... ugh, it's a good problem to have. :)

[@MrCarlsonsLab]

Thanks for your kind words William!

[@MrBrymstond]

Did yo use a laser printer for the protection board I heard you mention using a heated acid to remove the excess copper, I never heated the acid good idea. If you did use a laser printer on glossy thick card stock, what did you use to get the ink off? I may have missed this part. I noticed how clean job was so I know you didn't use abrasives did you?

[@gandalf87264]

Its so easy, this life saving procedure. Just touch all the capacitor connections. If you wake up on the other side of the room, you know that the one you touched was charged. Leave the amp for a month so for the capacitor discharge before you work on it again. :D :D :D

[@Deebz270]

Totally agree William. I'm zactly the same.

[@carlkeywood3135]

why he is just fixing amps why don't he make and designee them he would make so much more money

[@andrewpike2924]

That was a very good refurbishment. I think a lot of people would have given up and said it was too far gone. You actually not only restored it you made it batter than factory. Nice job.

[@MrCarlsonsLab]

Thanks Andrew! The Fella that owns it is a great guy, I'm just glad it has a good home.

[@rubusroo68]

2 hours well spent watching this, many thanks Mr Carlson. Great job.

[@MrCarlsonsLab]

+Rubus Roo Thanks for stopping by! Glad you enjoyed.

[@Deebz270]

I'm relatively 'old school' electronics.. (ex Radio Officer) And 40 years after my college and sea time, have got a tad rusty on my valve theory. You Paul Carlson, have taught me more and reminded me more of what I learned than any other reference. Your explanations and language are perfect for this discipline. You are one of my favourite haunts. I am currently designing my own guitar valve amp, with a sort of hybrid equalisation/filter stage and multiple output amp, giving me 3,15, 30 watt option. But what a beautiful amp this is. This is very close to my design cabinet, the loping front and control layout is how I envisage my completed design. Shudder to think how much all those trannies cost, if one had to replace them. LOVE THE CAPACITOR BLOCK MODULE ! Ditto for the 'Soft Start' / overvolt protection circuit ! . PS.Your videos (and those of Guitologist) have been priceless. Also your tutorials on the lab gear have reawakened parts of my brain, I thought would forever remain asleep. GREAT WORK MATE. But remember we have 240vac line voltage in the UK and 220vac in Europe... So some reference there would be helpful. Otherwise, keep up the fantastic tutorials.

[@MrCarlsonsLab]

Thanks for your kind comment, and input as well!

[@tefteulf]

Wow a 30W class-A amp from the thirties! Impressive! Mr Carlson, as being a retired teacher with 40 years of teaching experience, I would say that your teaching style is very attractive! I love the way that you mix good old analog equipment with modern digital ones. The "push one knob" measuring that you can do using today's oscilloscopes puts the student in a situation where they really don't understand whats going on. The old analog scopes are harder to use, but you really know what you are doing! In the video you measure the power output from the amp delivered to an 8 ohm load. The power measurements was carried out by some kind of HP-meter. If you do the same in in another video, a discussion of measuring the power delivered by a sinusoidal shaped signal compared to a nearly square wave shaped signal would be nice as I know that my students had problems doing the math for the two signals. (I mean in the video, the computer in the HP-meter was doing the math!).

[@MrCarlsonsLab]

Thanks for your comment and input Ulf!

[@brandysigmon9066]

Your knowledge is unmatched. You forgot more about electronics than I will ever know

[@robertvaldimarsson2109]

I love your systematic procedure and well structured explanations in your videos. I would very much like to see some kind of "trouble shooting manual"-video from you, as you mentioned in the beginning.

[@MrCarlsonsLab]

+Róbert Valdimarsson I will do that troubleshooting series soon Robert. Thanks for your comment!

[@plantopguy5]

Electronics guy for decades here but your videos impress the heck out of me. Thanks much for sharing your knowledge with us. The melding of old and new technology, wow.

[@MrCarlsonsLab]

+plantopguy5 Great to hear! Glad your enjoying the video's, and thanks for the kind words.

[@anotherdayisforever]

A NEW CARLSONS LAB! I saw you posted a comment on an EEVBLOG teardown video a few days ago and it made wonder when youd put another one out. Ive missed the refreshingly intense attention to detail your videos always contain. This was FASCINATING. Thanks!

[@MrCarlsonsLab]

+Cole Knapek Glad you enjoyed Cole!

[@slam854]

Happened on this video by chance and you drew me right in. I have a couple high-end vacuum tube audio components that utilize soft start in the power up and protection circuitry. Thanks for explanation. I am about to do a total capacitor replacement on a 1965 era shortwave radio and then realign the IF and oscillator circuit. Next come the trimmer caps and tuning coils. I owned this radio from new in my high school years and putting back in service. I like the way you problem solve, analize repair action and implement corrections. Your attention to detail is the sign of a great engineer.

[@pithandmoment]

Another outstanding repair and video. The capacitor block just takes the cake. Looking forward to the troubleshooting series. Thank you for sharing all this knowledge!

[@MrCarlsonsLab]

+pithandmoment Glad your enjoying the video's! Thanks for stopping by.

[@renekenshin6573]

I learn more electronics here than in college... You are one of best electronic guru's out there with videos that i never get tired of watching. Thanks for posting :D

[@MrCarlsonsLab]

Thanks Rene!

[@intothevoid9831]

What a fantastic video! Especially loved the part where you measured the frequency response, absolutely brilliant! You are a master of your craft!

[@MrCarlsonsLab]

+alex martin Thanks for the kind words Alex!

[@राकेशबंजारे-र9न]

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[@राकेशबंजारे-र9न]

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[@राकेशबंजारे-र9न]

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[@marcoalfaro6313]

Mr. Carlson’s Your Channel is the BEST of all of the videos that I been watching for the past two years. I was trining to figure out who can restore my Vintage HH Scott LK 150 Amp, LC 21 Preamp and LT 110 Tunner That i own since 1975 and everyone that i asked they told me that they were too busy. I thought that Blueglow Electronics was the best but after watching this video you are on top by making you’re own circuit boards and fixing all of the other things that some one else did, and making it wright for the customer you are worth every penny that you charge.

[@noslyguy]

The musician who owns this amplifier is so very lucky to have you as a electrical engineering resource. It is hard to believe you know so much about electronics. Very informational, and entertaining for the layman. It's only my guess, but I am going to say your services much be in such great demand. I can't imagine anyone who needed something electrical fixed, wanting anyone else but you to work on their equipment.

[@botvinss]

This video is pure gold. I wish to thank you for your meticulous work and amazingly thorough explanations. Sincerely, your new subscriber.

[@NathanOkun]

I am a computer programmer. I really enjoy how you plan for even low-probability problems by adding zeners and caps in critical points if something unexpected happens. In programming, the biggest problem is not making the program do what you want, it is making sure IT DOES NOTHING ELSE!! In software, this can be really difficult, since the number of unexpected inputs in a really complex program can be well nigh infinite, hence the success of hacking. You are a REAL PRO.

[@JoeGuitar]

2 minutes into the video and I subscribed !!!! I just love your videos !! This was sooo cool to watch. Any chance of doing more of these tube amp troubleshooting and repair vids? Keep up the good work. I'm telling all my tech / gear head friends about your channel...

[@MrCarlsonsLab]

+Joe Strabley Thanks Joe!

[@impetus444]

For a musician to meet a guy like Mr. Carlson is a dream come true. I cant imagine letting anybody else repair my equipment.

[@smallenginedude71]

what a wonderful video. very thourough and interesting content, your knowledge always impresses me. Hats off!!

[@doncampbellinc]

Awesome/ clear/ easy - relaxed- “common sense “to “? Confidence understood & unadulterated “ “Usuabld Valuable “-... “INFOmation”?!....Thankyou, Dj Campbell Jr.

[@AyFrame]

Just to say thank you Mr Carlson for taking the time to put these video's together, its much appreciated.

[@MrCarlsonsLab]

+AyFrame Thanks for watching!

[@jjcale2288]

Elegant soft-start and protection circuit, I can say! Young man, for me you are Arnold Schwartzenegger of electronics! 👏👏👏

[@TrueIndie88]

This is the most sophisticated analog tube start and protection circuit on the earth. Ingenious.

[@PaulDonnaErik]

Very professional arrangement for the big caps - nice

[@tectalabyss]

Outstanding job Mr Carlson.

[@MrCarlsonsLab]

+Bobby Tectalabyss Thanks Bobby!

[@ShawnsterZR1]

I love how you take every facet into consideration when you modify and enhance these devices. Every time I think of a "what if", it seems like you're reading my mind and answer it directly! Your attention to detail is simply unworldly!! Keep up the great work!

[@MrCarlsonsLab]

+Shawn Walsh Thanks for the very kind words Shawn!

[@janjohansenmusic]

If you were a doctor all of your patients would be healed!

[@BruceNitroxpro]

J J , AND.... not only would they be healthy, but would probably live to 125 years of age with no "leakage." LOL

[@janjohansenmusic]

cyberfloater That’s right I think. That you can precent substances to the body that makes the body fight the sickness. I try to keep my body alcaline and not acidic. Cancer loves an acidic body. Some cancer Don’t grow as fast or stops growing in a alcaline body some doctors have proven .

[@janjohansenmusic]

cyberfloater Why is it a great sin to be a alt doctor? Alfred “Dr Sabi” Bowman, Stanislaw Burzynski... I saw parts of a trial with witnesses saying that Dr Burzynski’s treatment were successful. But Wiki starts with this: “The Burzynski Clinic is a controversial clinic offering an unproven cancer treatment.” Not right. Wikipedia should not be biased. Who owns Wikipedia?

[@DRBLUESNYC]

Superb teaching style Mr. Carlson. Been an educator >25 years, prof at Columbia University and several European universities - and having taught countless lectures - your presentation style got me re-inspired to notch up my teaching and go back to spend some more time in my own electronics lab. Thank you!.

[@MrCarlsonsLab]

+Admir Hadzic Thanks for the nice comment Admir! It's great to read that I inspired you.... Comments like this make these video's worth the trouble.

[@DRBLUESNYC]

+Mr Carlson's Lab DO YOU TEACH PRIVATE COURSES?

[@MichaelLloyd]

What a cool old amp and you really did it justice in this video. I liked that you designed protection for it so it should live to play for generations By the way: Hister-ee-sis :)

[@MrCarlsonsLab]

+Michael Lloyd LOL, I will practice the word :^) Thanks for the nice comment!

[@BleedingHorseExpress]

After Mr. Carlson finished restoring it, I told him it would be an heirloom - and it surely will be! What a beautiful and amazing sounding 80 year old amp. I'll enjoy playing it for many years to come!

[@jfelix3523]

Mr. Carlson, I only recently stumbled across your channel. I love watching your restoration of old radios, but this amp project caught my eye because I play in a band. I was excited to see your soft-start circuit power up, but I was not expecting a full test of your protection circuit, and I got a little nervous as you dialed up the line voltage past 120V. When the B+ got to 500V and the protection cut it off, I actually stood up and cheered! Thank you for an excellent and informative video.

[@BurtonBoyz715]

Very clear...very detailed....a great tour in trouble shooting......Great narration.....as if a walk through the jungle with an expert guide....thanks...... I'm subscribing.....; )

[@MrCarlsonsLab]

+William Earney Thanks William! Glad you enjoyed the video.

[@mikesamra9126]

+Mr Carlson's Lab This is precisely the reason why I don't stuff cans or do what that other tech did because they do need to vent and I would have used a dual 50uf 500v or a dual 32uf at 500v or even a dual 100uf and then add the 3rd cap somewhere else that is electrically the same point.I realize the cap failed from over voltage but I still believe in being cautious..Excellent video as usual.

[@curtisroberts9137]

That old amp is truly beautiful when all together. Great craftsmanship and design. Now that you have added a modern dose of craftsmanship and care it will continue to deliver its beauty to the world. Like an old car restored and being driven daily. Thanks for sharing.

[@Mcbeth2pl]

Wow, electronic engineer. Complex puzzles. Exceptions to this rule and that rule, and then exceptions to the exceptions..... Man You don't have to worry about dementia (Good memory). You got me Soldered from start to finish on this video. Very descriptive, concise and comprehensive. Some people charge money for your knowledge. Subscribe.

[@MrCarlsonsLab]

+Mcbeth2pl Thanks for your kind comment!

[@chriscunningham6362]

I restore vintage electronics (mostly tube amps and Tube radios). Your understanding of the electronics is amazing considering your young age. I love your videos and set through them beginning to end. They are very educational and I have picked up some great tips from you. Also, love your lab!

[@MrCarlsonsLab]

Thanks Chris, glad your enjoying!

[@olisent6867]

"Listen here amplifier...." "......No more surprises......." Gave me a good chuckle..

[@BleedingHorseExpress]

Me too. I still play through this beautiful amplifier often - one of my favourites.

[@rimmersbryggeri]

You are so right. Alot of people go about both repair and construction in a very obtuse manner. It's almost like they want to make things look super complicated so that they can look very intelligent to people who don't understand what they are doing.

[@derbigpr500]

It took 2 minutes to get me to subscribe.

[@MrCarlsonsLab]

+derbigpr500 Glad your enjoying! Thanks for your comment.

[@abc-ni9uw]

me2

[@jagardina]

I grew up playing with tube stuff back in the 1960s. Your warnings are just common sense to me but well justified. I've suffered more than a few ouch moments that could have been much worse.

[@bitteroldskunk]

That is a beautiful amp. I would love to copy its cabinet and lay out to build a 'close to original' ground up replica of that.

[@MrCarlsonsLab]

+shortwave It definitely is unique.

[@gfighter2400]

I’m transfixed every time I watch your videos, Mr. Carlson. My hat goes off to you!

[@TRXLab]

As always great video Paul! Can't wait for the next one! Take care

[@MrCarlsonsLab]

+TRXBench Thanks Peter! Holidays are over, now we want video's! LOL! hope your holidays were great!

[@TRXLab]

+Mr Carlson's Lab LOL yeah videos are already in production and coming soon. Holidays were great.

[@MrCarlsonsLab]

Great! I look forward to your next video.

[@stevenkaeser8583]

I watch these long after they’ve been recorded and they never seem old. That’s a good trick 🙂

[@Thermionman]

Interesting circuit there for voltage limiting !

[@horseshoe_nc]

My knowledge of electronics is limited. However, I've always enjoyed your videos, even though most of it is over my head. What I do know, you really go the extra mile to provide the best service possible.

[@tm80notgoodwithnames58]

372 likes and no dislikes. Great job!

[@Tennisplayer21Kim]

I cannot believe this extremely high quality EE video is available to us for free! I watched the whole thing twice, so great thanks!!!

[@MrCarlsonsLab]

+Tennisplayer21Kim Your welcome Kim!

[@rjcool9251]

YOU have so perfect experience and an excelent job god bless you

[@MrMersh-ts7jl]

I have watched this video numerous times over the years and am just amazed at the simplicity and complexity married together in the soft star over voltage. Also after watching all of your videos I have a feeling that whiteboard was only drawn on once haha. I am wishing that I had someone like you and I was younger to apprentice under

[@Okanagan48]

You are one smart young fella. Like your videos greatly. :-)

[@MrCarlsonsLab]

+David Okanagan Thanks for the kind words David! More video's like this to come.

[@richardcline1337]

Those two big 'scopes on the upper right sure brought back some good memories. Those plug in modules gave them so much more capability than many believed when they first came out. It saved having to have so many different scopes around doing different things. I miss those days but that was decades ago for me.

[@SciPunk215]

Who the hell gave this vid a thumbs down ?!?

[@mirrorrorrim5623]

Very jealous ppl

[@Washburn-rr5eh]

Some very jealous people. This guy is truly amazing!!

[@MrCarlsonsLab]

+Mirror rorriM Thanks for the kind words!

[@AM-yj5yc]

Mr. Carlson's like:dislike ratio is incredible, I am almost positive it's the highest of any channel I've seen, and across all his videos too. I still find it strange that even a few people can bring themselves to click the dislike button.

[@sangeeth_619]

Excellent service tutorial! The amount of detail that you dive into has to be greatly appreciated. There is no other channel in KZbin that gives this much information for any single product. Really appreciate your effort and dedication when making these videos. Keep going.

[@MrCarlsonsLab]

Thanks for your kind words Sangeeth!

[@silasfatchett5693]

In the UK it's 'hiss-ter-REE-sis'.

[@MrCarlsonsLab]

+Silas Fatchett LOL thanks!

[@KozmykJ]

Fascinating stuff. I'm an old 70s trained TV repair and production technician. Later transferred these skills into sound engineering. It's great to see all this old valve stuff being restored. I've got a couple of valve amp jobs to do myself. Selmer Truvoice Concord 8 combo and a Selmer Treble&Bass 50 head. Been putting them off. Hopefully recapping will be the worst of it. Your vids have given me some extra points to look out for .

[@davidmckee5659]

"I'm Bad at the one word, 'Hysteresis' - perhaps the only thing Mr. Carlson is not good at is pronouncing that word. :P

[@birdwing98]

hiss-tur-EEEE-siss

[@BruceNitroxpro]

David Mckee , And as a teacher, I never said a WORD! LOL Some words refuse to be pronounced correctly, possibly because so few people know what they mean. Paul uses the word knowledgeably because he may not SAY all the things he knows but knows what they mean!

[@davidmaddison2628]

You are a genius, Mr Carlson. Superb job. Your attention to detail and doing things right is just amazing. Most people of your young age would have no clue about, or interest in any of this stuff.

[@MrJohn1966elliott]

Wow, You're so clever ! Huh ?. : P

[@Synthematix]

I dont want to make your head swell Paul, but you really are the master of electrical engineering

[@demonkey123]

That cap bank arrangement you have devised gave me a warm fuzzy feeling, like everything is right with the world. Beautiful job 👍

[@MrCarlsonsLab]

Thanks!

[@ao2528]

Rarely I can handle to watch 2 hr. movie or video from start to finish, but I was nailed at my seat and finished watching your video non stop, thanks for really, really interesting content of this fantastic informative video.

[@michaelayliffe7238]

Like the way you have respectfully worked with the design and the past repairs as a point in time. The design is what it is, then you put your own science and desgin. Nice work

[@MrCarlsonsLab]

Thanks Michael!

[@Thomasp671]

Mr. Carlson you never miss anything in your description of the unit or the problem.

[@peep39]

This is not the first time I've watched this video. As someone that is self-learning electronics, the portion of the content you devoted to the soft start circuit is incredibly instructional. My interests are in audio amps and linear power supplies, so your channel is gold to me.

[@grngs1]

Where did you learn all this? You must have a natural talent for this, you speak very fluidly and are comfortable with electricity. You should do a video covering your history and how you became so talented in this.

[@harryconover289]

Excellent work been working on big tube amps since I was 14 , I'm 63 now , very nice to have a good exclamation of work done and how detective work on the units repair history Harry .

[@MrCarlsonsLab]

+Harry Conover Thanks Harry!

[@stridermt2k]

I just finished watching this and once again a piece like this one demonstrates the NEED to have someone who understands it do the work. As always it was a pleasure to take a journey along with you and be wiser at the end. Thank you and 73 DE N2NLQ!

[@johngalt5205]

I discovered your channel through Technology Connections --> TechMoan. I own a software firm, and I can really appreciate your dedication to attention to detail and subject knowledge. The vast majority of people I have run across in my arena just slap stuff together and pray it works. I also like how you spend the time to explain what you are doing and why. Subscribed.

[@MrCarlsonsLab]

Thanks for your kind comment Carl!

[@mikehanks1399]

I have absolutely no idea what you are talking about but I watch anyway. Your expertise is incredible, that much I can understand.

[@Tommyinoz1971]

That was excellent, I'm very impressed. I loved the soft start/protection circuit modification and I also loved your capacitor block solution. Your attention to the little details is great!

[@tazience-colvard3850]

Totally top shelf presentation. Nothing left out. It does my heart good to see such thorough professionalism with vintage electronics from someone so young. I learned some things and discovered things that I may not have thought of had it been my project. A true paradigm reversal of attention to where innovation in electronics was the norm and understanding can still be made interesting.

[@MrCarlsonsLab]

Thanks for your kind comment!

[@AlexDeLarge1]

This is perfect late-night content. Very satisfying and relaxing stuff.

[@fall-of-rome]

I'd love to see you design a stereo amplifier to the best of your ability because you are so incredibly talented

[@joem.4359]

You lost me at Hello! Almost the same as in the movie but not quite :). I've been watching for about 5 hours now, can't stop. No kidding, you're a freaking Genius! I have very little understanding of what you say, but I have picked up a few things. The knowledge and understanding you have; the command you have of the lingo; and the way you demonstrate everything, I'm blown away. You should be working for NASA. Your obvious love for electronics and your expertise is one thing. However in stead of being arrogant you are very humble, and even kind. When you could have trashed the tech that first "got into" the Thordarson T20W40 tube amplifier, you handled it very professionally and as a gentleman. The fact that you so willingly spend a huge amount of time doing this for us, at no cost speaks volumes as to the kind of person you are. Actually, you could probably RUN NASA, but I think your true calling is indeed that of a teacher. I've been trying to find help with a little 5 Watt Bugera amp that I messed up and that's how I came across your videos. Wow, what intelligence and passion. I'll keep coming back just to try to learn a speck of what you know. Thank you and be well.

[@MrCarlsonsLab]

+J. Mack Thanks for your very kind comment J.Mack! Glad you enjoyed the video.

[@leowiuker6989]

Your videos are great to say the least !! It surprises me how a young guy like you still working around Vacuum tubes !!!(yes I'm older and from older school) I moved to the US from South America about 17 years ago and when I tell my colleagues that I had to studied them, Germanium Transistors, making memories with 1000's of micro-donuts magnets they look at me like I'm a space Alien !! I love Vacuum Tubes and the quality of sound is something else. GREAT JOB !!! Very absorbing and no detail left out !! Keep the great work ! I'm sure you will get a huge following ! EXCELLENT !

[@MrCarlsonsLab]

+Leo Wiuker Thanks for the kind words Leo! Great story about the toroid memory.

[@jessemontano6399]

Waves through the quantum (electron) field... The radio is full of moving parts.... It amazes me to no end...thanks so much, prof Carlson

[@gripper021164]

Great vid as usual, you are what we call a proper engineer in the UK.....Much appreciate these very informative videos that you give us the privilege of watching......Many thanks.....

[@MrCarlsonsLab]

+gripper021164 Thanks for the kind words!