Amp Repair And Restoration - Kay Model K550
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- เผยแพร่เมื่อ 30 ก.ค. 2024
- Tons of information to help you repair and restore amplifiers! Lots of tips and techniques that you won't find anywhere else. In-depth component testing and more! Click the SHOW MORE tab below for links.
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: / mrcarlsonslab
Capacitor video displaying ceramic disc noise (and more) Here: • Which Capacitor Do I U...
#learnelectronics #restorationvideos #repairvideos - วิทยาศาสตร์และเทคโนโลยี
To learn electronics in a very different and effective way, and gain access to Mr Carlson's personal designs and inventions, visit the Mr Carlson's Lab Patreon page here: www.patreon.com/MrCarlsonsLab
Thank you!
@@michaelraymondellis6997 You're very welcome Michael.
Mr. Carlson, I can only imagine your history of electronics knowledge. I'm in awe with every video I watch. I'm lucky to know the difference between a cap and resistor. Thank you for efforts on your videos.
I wonder how much that cost? A very fine job!
I usually stay away from audio content because of all the pseudoscience and ridiculous claims people make. But it's nice seeing your input on these audio restorations with an actual basis in science, without the nonsense people inevidbly get into with capacitors, or whatever.
In my mind you are Doctor Carlson, a true master of electronics
The Professor.
Crazy! I know this is a bit old, but I was just thinking exactly that. Dr. Carlson. A master of electronics, and a master of explanation.
I was going to write the same thing in my comment and saw yours just before I posted. You are bang on!
Amen, brother…….! He is. Truly extraordinary!
Yes. Prof. Carlson
There are experts and then there is Mr Carlson. An order of magnitude greater than your "normal" expert!
Mr Carlson's Lab is the best electronics show on the web!
I have to second this assertion.
Big Clive is pretty amazing as well!
@@chrisa2735-h3z what’s “Big Clive”?
Your tip on how to check speaker polarity came just in the nick of time. Yesterday I repaired an old speaker with a new surround, and I had no idea how to determine the polarity, because the manufacturer didn't mark the contacts. At first I thought that, since I don't have any resistors, I wouldn't be able to do the check. But when you did it without the resistor, I went ahead and got a clear movement of the cone, apparently without any damage. Many thanks!
I recently got out of the hospital after over 4 months (COVID is no joke). My wife was aware of my enjoyment of your videos and had the nurses play them, as wel asEEVblog, and big Clive while I was unconscious in the ICU. I’m so glad to be able to enjoy them again. Thanks for the time and effort you put into these posts.
you are the most generous teacher
Thank you so much with providing us with such high quality repair and restorations here on TH-cam for all to see.
its honestly unbelievable that such high quality content is free on youtube.
After a hard day's work, watching this is the perfect relaxation. Pretty sure Uncle Doug is going to enjoy this one.
Absolutely! Exactly what I feel!
I never comment on any of your videos, simply because I do not know what to say, but I think this is overdue, thank you very much for your quality content. I enjoy every single one of your videos, moreover, THANK YOU for not dividing them into 12 parts like everyone else. I have severe PTSD, Ham radios and electronics help me keep my mind busy, and watching your videos helped me deal with my condition due to your very relaxed approach. I love the effort you invest in the quality of your audio, I can feel a true HAM at work. What I would give to have an Elmer such as you. Please never stop making videos.
Paul, so glad to see a new video from you. Hope you and yours are well.
Mr. Carlson - I was hoping we would hear you doing some guitar shredding on this repaired amp, very nice video.
Me too, Mr Carlson can repair anything, but can he shred? Lol
@@dave1135 We need to hear some Iron Maiden thru that vintage beauty
+1 for shred
+1 for shred
Phone number chahie
I attended the Connecticut school of electronics in the 1970s and learned everything from individual components to microprocessors which were new at the time and very simple compared to today. It was a great electronics course and I did very well at job I had at the phone company which I recently retired from. The thing is every time I see one of your videos I often wonder if I had a teacher as great as you how different my life would be! You are the best teacher I’ve ever heard I learn so much every time I watch a video and you are so inspirational it’s amazing! God bless you!
There are so many repair tricks in here it's fantastic. I never thought to check how noisy the resistors are with a signal tracer. I always went by condition and value, this will make my repairs much better, ty! That and I never thought about speaker phasing in a two or more speaker system. I'll never miss that one again. Im a patreon member and I need to start following there more closely. The library of information you have built up here is amazing. Thank you for passing along this treasure trove of knowledge and practical experience! I have a EE degree, but none of that education covered the practical things I've learned from you. Always learning, always growing, and you've made that easy to do, thank you!
I could sit here and watch you repair/restore electronics all day everyday. You are a hell of a mentor thanks for the great lessons over the years Mr Carlson your awesome man😊
Thanks for your kind comment.
I’ve said it before, nobody does it better than Mr. Carlson. Really enjoyed this and loved the demo of the noisy resistors. I actually bought one of those signal tracers based on your suggestion a while ago and like the noise test feature.
I ran into quite a few noisy wire-wound resistors in an amp I restored a couple of years ago. I actually diagnosed the issue using Super Freeze electronics spray. So, similar to your heat test, except going the opposite direction with temperature.
When operating the amp and spraying the problem resistors with Super Freeze, the amp instantly started playing properly and quietly. When removed from circuit and connected to an ohm meter, I could clearly demonstrate how the resistance of the problem resistors fell into their rated tolerance when sprayed with the coolant. And, as they warmed up again, slowly returned to much higher resistance.
So, the expanding/contracting of the resistor not only created noise, but also changed the resistance. I ended up changing all of those wire-wounds. There’s a video of the Super-Freeze/Resistor demo on my channel if anyone is interested.
A dry-wet solution in a single package. Must be a great amp. Thank you Mr. Carlson!
I found an old Kay 703 a few years back; got it for a song, as it didn't work. After checking through the chassis, all the components were still to spec with the exception of the multi-stage filter cap. I left it in place, soldered in 3 elcos of the appropriate value, and she now works like a charm in all her 2Ws of glory.
The topic of today's video is more involved than anything I'd have thought Kay ever contracted for (they didn't build their own amps); the Hammond reverb pan was a total surprise. My guess is that this little jewel had some tone in its day, and that the owner used spit, baling wire, duct tape, and whatever else was available to keep it working as long as he could.
The Kay was probably made by Valco.
Thank you Mr. Carlson.
For being the one and only tech I know of who recognizes the art and value of impierical design work that went into the things.
You are very welcome Steve.
Hi,The level of detail you go to is beyond... No one of my teachers ever explained anything about the outside foil on caps! Thank you sooo much!
Glad it was helpful Denis!
This was a very good one. The resistor noise demonstration was impressive and totally new to me, i only ever heard about that in theory - it is quite a different thing to have it actually demonstrated. I also loved how you showed how to not puncture the speaker membrane. It is this attention to detail that is unique to your videos. Most people would not even think it possible to explain things down to that level of detail. Most of us figure things like that out after some decades of tinkering, but having it taught right away from a master saves lots of time and frustration.
It’s such a privilege to see these amazing restorations. Thank you.
I love when he does amplifier videos! Love watching the master at work.
It's really amazing how you get something on the bench and then take your time to tell the whole story in a timely and orderly fashion, clear cut and simple, laying back on basic electromagnetic and physical laws helping to put the whole restoration (or whatever you take on doing and filming it) in a much needed clear perspective. This is not only very professional, because all your content just is, but your teaching and tutoring skills really come as a surprise in this field. Most tech wizz staff will have a very difficult time to even socialize in any coherent way, let alone explain, teach and convey proper and useful knowledge and experience, while maintaining a very lively vibe along 90 minutes of video. Bravo, sir, and thank you for another great hour and a half, it got me immersed better than a favorite movie!
It always amazes me how good your audio/voice sounds like when you speak into the microphone at the beginning. Warm, clear, no background noise... Kind of ASMR.
It's like he's in your speaker talking to you, stunning quality
While I greatly admire Mr. Carlson's expertise on most things electronic, I must take exception to the AC wiring of this amp. The "death" capacitor going from the fuse holder to chassis ground means that for correct polarity the fuse had to be connected to the Neutral wire of the AC cord. Also note - the power switch on the "Contour" pot was also then connected to the Neutral side of the AC. This was done intentionally to reduce 60 Hz hum into the audio path via the AC switch proximity to the audio signal through the pot. When adding a three conductor AC cord to such an amp, the Hot should go to the fuse first, as Mr Carlson noted, BUT - the "death" cap is now connected from the hot side of the line to chassis. If you lose the ground connection of the cord via a bad wall socket or extension, the chassis will now be energized by the capacitor. As long as the cap is in good condition you will only receive a mild shock, should you come in contact with a grounded surface. But if that surface is a vocal mic, the shock to your wet lips can be rather painful. There is no necessary function for the "death" cap once the AC cord has been updated. Just remove it and leave it out. The other thing to sort out is whether to connect the hot lead from the fuse holder or the neutral lead to the power switch. Given that the switch on a pot is likely to pick up hum from the hot 120V, I usually opt to switch the neutral line. This is the only situation in which I would advise this. Besides the hum factor, which may or may not be significant, depending on the particular amp, (I've found some amps with the switch on the Volume control which makes them very sensitive to hum) there is the safety factor of having live AC voltage on the pot itself. That is my major concerns regarding this video. The rest of Mr. Carlson's work looks very good, and the capacitor test box is most interesting. A job (mostly) well done.
Many amplifiers fall subject to RF interference, bypassing this issue with capacitor across the line cord will greatly reduce interference from CB's, Ham radio equipment, and even near by cell phones. This capacitor is also effective in reducing commutation noise, (the more popular of the bunch.) The line capacitor looks like a low impedance short to many RF frequencies. That's what that cap is "really" there for, aside from popular belief. Reducing hum due to phase cancellation (what you mention) is just a bonus.) In radio receivers, the line bypass capacitors couple the chassis to line for RF purpose again. The 22K resistors on the audio inputs are a non-inductive path for the audio circuits in the front end, these resistors will help keep RF out of the amplifier chain front end circuitry due to long audio cables acting as antennas. "Common Mode Interference" is still an issue, but these resistors greatly reduce that problem. So in short: Any techs that get rid of this capacitor are making a mistake, and don't understand that capacitor's true purpose.
Regarding the line cord: Please note that you effectively have two of the same points tied in a breaker box. In most residential and commercial wiring, the neutral and earth connections are joined in that breaker box. You now have a line cord that will only plug in one way, "and".... A neutral and earth connection that are configured correctly as well, due to the plugs ability to only fit one way. This does not account for an incorrectly wired hot an neutral, but you still have an earth connection (that's connected to that neutral) in the panel for added safety at the amplifier.
I’m an idiot when it comes to the things you work on in your videos , but it’s always a pleasure seeing you work and hearing you explain things . You have a great channel and skill on a level most of us can’t comprehend. Keep up the good work , Merry Christmas to you and your family , see you next video
This capacitor is excellent a very high quality capacitor it tests perfect with a very sensitive tester .......Lets replace it lol.. Great Video Paul
Where was the capacitor autopsy? We want to see the gluts ! LOL
Excellent video I realy like your way of explaining theory of operation thats the hardest info to gather from available sources thank you paul
Glad you liked it
Yes Paul theory can never be over rated I am a retired Ford electronics tech the most over looked section in a repair manual is
Description of Operation .I often times wondered how one could attempt to repair a failed system if he did not fully understand how it was intended
to work .Again please don't stop short on the theory of operation because its a very nice touch thank you again. I also notice with every project in every video there is a beginning and a completed end to the project you never not fix the item or give up and the ending closer display is a finished repair .Some channels are all over the place with at the end of the video no completed repair or a part two or three or a failure to fix the item your channel has high standards and that it would seem to be part of your make up thank you for allowing the viewer to be a small part of the process by indorsement of your channel
Paul from Michigan the Great Lakes State
Paul, the best thing was checking the speaker phase before finishing the unit. Most repair folks would have waited on that and if the phase was wrong they would have botched the primary wiring to fix the issue, leaving the next technician scratching their head. Thanks as always! And your Patreon page is worth every penny too.
As one speaker is the reverb you can still flip the phase in the reverb unit and in or out of phase may be more of a personal choice than with a real two speaker box.
Its me again. Just got a new sds1000x-e oscilloscope. A lot of bells and whistles that i don't understand yet. Learning something new everyday, thanks to you. Thank You !!
FANTASTIC little gem of a channel!
Thank you kindly!
And here I thought we were gonna see Mr. Carlson playing the guitar! ;)
I would like that.
What a Kool amplifier
Hi Paul. I have been a guitarist all my life in many bands since late 70's. Years ago I have had bad shocks from amps and microphones. I am a testament to the probles. Thank God todays tech as yourself know the danger. Thank you for your videos.
I'm not a electronics person, but watching your video was very interesting. It gave me a better window of understanding how a amplifier works. Thank you.
Jack,
II think if you go back and look at one of Paul's videos called "how a tube works", you will understand a lot more about how old amps work.
Ian
@@ianbutler1983 Thank you Ian. When I get the chance, I certainly will. Stay safe.
I would just throw away all worn out electrolytic capacitors. I wouldn't leave them in the amp. And I certainly wouldn't stuff them with new ones. And I've heard that a C or D battery is safer than using a 9-volt one for testing speaker polarity. I really enjoy your videos. This was an excellent restore.
You're right Zac, a 1.5 volt battery doesn't need a resistor to test a speaker safely.
1:29:42 "Electronic tonalities" for the win! (…except for an Oscar, apparently). You did an amazing job bringing it back to life, the inside sounding (and looking) as gorgeous as you and the other fellow did with the outside. Thanks for bringing us along for the journey.
This wasn't just a restoration. It was a renewal. Thanks, Mr.C
My Pleasure!
Great looking and great sounding amplifier. And you did a fine job teaching. I’m glad you brought us along on this restoration.
Brad
Great format, great information, the best audio of any site on the net. Thanks for all the time you take!
That was fascinating tests on caps & resistors. Never knew that you could "listen " to a resistor. Thank you for taking the time to make this video. God bless.
Thanks Sallie!
Having repaired and restored a few Hammond organs in my time, I recognized that reverb as soon as you took the back off the cabinet. It brought back some good memories. Thanks.
I am passionate about sound, and so seeing the science behind the sound through this restoration has been relaxing and generally wonderful.
Really a nice restoration. Strange design. I did a similar restoration on a tube amp Leslie speaker and modified it to take a line input from the player's new Hammond keyboard and of course power on without having a Hammond B3 hooked up to it. It was hard to preserve the glued paperwork on the chassis and still refinish it. I replaced the bearings in the rotating drum. When I was removing the drum a wasps nest fell out (YIKES). It almost got me almost as excited as when I didn't discharge the filter caps in my Marshall 30 years ago. There's a mistake you'll only make once. Beautiful, thoughtful work as usual Mr. Carlson.
Ain't gonna lie, I was kinda expecting Mr. Carlson to pull out a guitar and play the heaviest riff ever. Jokes aside, nice video, very educational.
Thanks Ciro!
I am especially impressed with the restoration of the case! It is very time period Correct!! Also I love when people leave the patina behind- it's showing how much it has "lived" so to speak.
I can’t stop watching and admiring your videos Mr. Carlson! Thank you!
Glad you like them!
Mad props for preserving the character of the amp by things like keeping the ceramic caps! 👍🏻
That is so interesting about microphonic capacitors being an "effect" feature that adds to the personality of the amp!!
Really like this video allot of interest and inside info. After 50 years. You are the Mr. Rogers and Mr. Wizard of antique radios. Remember Melting old transformers in a toaster oven to replace some if's .
This was an involved video and you showed some effective troubleshooting as usual. Got it to be real quiet after that workout. Good job Mr Carlson! Stay safe mates!😊👍🏻😷
Cant tell you how much you've helped me in this field..thank you for taking the time to share your knowledge.
Glad to help!
In modern equipment the transistor blows first to protect the fuse.
LOL, correct you are!
Would've been nice to have seen the "hand drawn" schematic as an example of the genre.
another terrific restoration Paul - super quality work and some great insights into components and design... many thanks
I’ve watched several guitar amp repair channels on TH-cam. It’s great to finally see someone competently repair an amp. From a fellow engineer, I learned more from this video than all other channels I’ve visited. You not only spared us of reckless and cringeworthy fumbling; but, you also excellently explain your process and reasoning. Top rate quality video!! Thank you for raising the bar higher.
First Mr Carlson video where all original caps tests ok! Wasn't expecting that when first seeing the condition of the amp!
Good Job Mr. Carlson. The opening of the 1951 Sci-Fi flick "The Day the Earth Stood Still", pleasing vintage Sci Fi noises..
This is some real A+ tier work you do Sir. Well done and thanks for sharing
Hey Paul. I am glad you mentioned the disk caps being microphonic and adding positive feedback to the sound of the amp. Also back in the days of 10 to 20% tolerance its far to say that every amp had, like you said it's own personality. Good work as usual.
Thank you for this video! I learned SO MUCH about older components!
My brain explosion for the day. Excellent. 👍
Good ole Johnson/Nyquist noise, great demonstration!
Frost morning.....BIG mug of coffee and a Paul fixes something video. It doesn't get any better. :-)
I know next-to-nothing about electronics, but always enjoy these and always learn something I can apply later! Thank you & keep the lessons coming.
ripper video as always. man i could never remember all these old timey types of resistors & caps
Mr. C, you are the coolest guy on TH-cam. Thanks a bunch for this project. It is fascinating and much appreciated.
Thank you Mr. C! I'm still learning a lot from your excellent videos!
You and my Grandpa would have gotten along famously. He was a World War One Vet, and he started building crystal sets in about 1914. He learned the Morse code by listening to ships out on Lake Michigan. This was before any commercial broadcasting existed. He was thorough and meticulous, same as you, and he taught me the fundamentals of all this at an early age. Watching you work reminds me a lot of him. He was a real good guy, and he could fix just about anything.
That little amp is probably going to be a really first rate studio rat. Good ribbon and condenser mics will probably make it sound like God shouting from the mountain top.
outstanding video again !! I was just thinking about you two days ago. That I have not seen a new video for a time. Now we know what you were doing. Great trick on the resistor. The space sounds took me back to the movie "Forbidden Planet". Thanks for the time and effort you do for the videos and for us. I hope you and the family are safe and well.
Having seen how the amp was internally wired to the mains cord and the fact it was a non-polarised 2 pin plug, I have made a note NEVER to plug my guitar into anything old ever again!!!!! It’s a wonder your customer lived long enough to employ you!!!!!
We learn so much from your videos.
That's a very interesting characteristic of the ceramic caps. I've been an electrical engineer for 37 years and I tend to think I've seen it all...and then I watch your videos and learn something new nearly every time.
I like capacitor and resistor knowledge and insight. I don't do electronics, but I do watch it and your show is really stimulating. Your craftmanship and skill is outstanding. Cheers!
Very interesting video - I am always amazed at how you can reproduce the function of old equipment and repair it 👍
Wonderful video. Love your teachings. Thank you for sharing this knowledge. It's rare to find it. Grateful. Please keep it coming!
Always great info and a learning experience.
I watch you're videos all the time. Great job 👍.
The new toltex on the amp looks absolutely AMAZING. the chrome cab corners, the piping, fresh chromed handle. Amazing looking amp
Hello again! Great job on the rebuild. I loved the way you pined over esthetics which most never address, plus it makes it sound better looking new. :) The ONLY aspect of the rebuild that made me go "what?" was the missed gang connection between the amp and speakers for ease of removing amp without disturbing speakers. Other than that very helpful and insightful!
As an old tube guy, this was GREAT!
@ 08:00 Heat insulation with a lighter first, makes a huge difference! Excellent video Mr Carlson, superb tips.
Beautiful...restored! I love you, Mr. Carlson!! lol Great clip, as always.
I must commend you on your videos. Very informative with good explanations.
I'm attempting to repair a 9 tube RCA console where I dont have voltage on the first and second IF stages but if I watch enough of your videos, I may figure it out.
Thanks for your videos.
Great restore. Nice looking amplifier im sure the customer is going to be very happy.
So meticulous! What a labor of love. Thanks for sharing
This is my new favorite You Tube Channel! Your skill set and knowledge level of electronic theory amazes me. My brain is like a sponge trying to absorb all that great information you share. Thank You for these fantastic videos!
Glad you enjoy it!
That was both fun and educational. Thanks Mr. C!
I like your observation and comments on the glass jewel pilot lamps. I have some red and green ones from way back.
Lovely job Paul. Someone will be delighted to receive this back.
Thank you so much again Mr Carlson. Great overhaul. I really was surprised by the way those filament wires not caused AC hum by the way this was wired fabric. I really need to check this fantastic circuit by daytime again( it’s 3 o clock at night here 😁). Again many thanks 🇳🇱
You Sir are my personal hero.
Beautiful restoration as usual Paul.
Really like the full length video where you go into lots of detail
Great video 👍, great repair/restoration 👍 as always!
Learned something: it's not the SPRINGS that make the reverb, but the little pickups at the ends of the springs... the springs are like "diaphragms" in a microphone. Very nice! Thanks! Excellent as always.
Love Mr Carlson's fine attention to detail. Award of Excellence in Education.
The reverb setup in this amp is the same setup Hammond used on the A100 organ models. So there is the internal power amp (AO-39) driving 2 speakers, and the reverb amp (AO-35) that takes its input signal from one of the clean speakers. But one interesting thing there, is that the reverb intensity potentiometer is wired between the reverb amp and the reverb's dedicated speaker. For what I understand, that pot is also acting as a resistive load when it is at 0% reverb.
I am not sure if I would have been as focused as I am today watching and learning from your videos but I wish I could have you as my physics/electronics teacher.
Subscribed and already a Patreon. Keep up the great work!
The subject of tube amps is really interesting to me.
Another Carlson spectacular 🇨🇦🇬🇧
I really enjoyed many of your videos but this one is my favorite thus far. I would have loved to hear someone playing guitar through that when it was done.
Excellent work Paul. Very nice job!