Amplifier Troubleshooting and Modification.
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- Опубліковано 22 лют 2018
- In this video, we look at some issues in amplifier design that are not so talked about. We will address these issues one by one until this amplifier is working properly. This video can be viewed as a continuation of the previous AES Six Pac Amplifier video seen here: • Two Six Pac's On The B... To learn about electronics in a different and very effective way, check out my Patreon electronics course here: / mrcarlsonslab
- Наука та технологія
To learn about electronics in a different and "very effective" way, check out my Patreon electronics course here: www.patreon.com/MrCarlsonsLab
have made mode of your super probes to sell?
concur. highly recommend mr carlsons lab on patreon. paul teaches in a way i understand i have learnt orders of magnitude since following.
gg
I'm a retired EE, 40 years in power analog and RF. I have never seen anyone present electronics in the same manner that my grandfather taught me (and started a lifelong love) ...until seeing your videos. I am beyond impressed. Your series should be required coursework for undergrad engineers and trade schools. Well done, and thanks, I've re-learned a few old guy tricks.
Yes, and yes, yes, yes. Not my grandfather, but an EE prof at the local university who was a ham radio operator.
The person who owns these amps is fortunate to have you as a friend to repair and upgrade them. We, the viewers, are fortunate to have you as our instructor to explain and show us how you did all of it. 10 thumbs up for this one.
I can't express how much I love watching these videos. You are like the Stephen Hawking of electronics. The way you explain complex (for a layman) circuits in a comprehensive and entertaining way, is unrivalled. You have me sitting through up to three hour long videos and enjoying every minute. Outstanding work.
Morten Sundal _ couldn't have said it any better! The video style and teaching style is awesome... Relaxing and super enjoyable. It goes so well with tube electronics. I have always had a happy fascination of them since young.
I couldn't agree more, Morten. What a brilliant teacher! I know next to nothing about electronics theory, but he makes videos that are well thought out, intelligent and easy to follow for non-specialists.... Just incredible!
Yes, amazing videos. I spend hours watching them. I share them with my kids too. I want them to understand electronics.
I'm constantly amazed by your tremendous depth and understanding of electronics, from making coils, fixing parts, restorations, to even a desire to share your expertise in an entertaining way. Been a tech for almost 50 years, I sometimes feel like a beginner after watching your videos - you have re-inspired me! Thanks. Jon
I TRIED TO EXPLAIN TO MY FRIEND THAT RUNS SIX PACKS THAT THE HUM IS PART OF THE DESIGN AND THEIR IS NOTHING HE CAN DO EXTERNALLY TO REMEDY THE NOISE !!
IT IS INHERENT IN THE DESIGN, SIMPLY BY THE PROXIMITY OF THE COMPONENTS !!!
YOU HAVE VERY NICE INSTRUMENTATION !!! NICE TO HAVE SELF CONTAINED MATCHING LOADS IN YOUR MEASUREMENT EQUIPMENT !!
I ALSO HAD A HARD TIME EXPLAINING THE BIAS RECOMMENDATION WAS ONLY TO GET YOU IN THE BALLPARK !!! THE ACTUAL BIAS WAS MUCH LOWER AND IS SET BY WATCHING THE CROSSOVER POINT ON THE OSCILLOSCOPE !!!
I like Mr Carlson working repair old radio and explain everything!
Before you repair the second amp, please plug in a speaker to each so we can hear the difference in sound. Thanks, great videos!
every film by Mr C is auto thumbs up. what a gem of a channel.
Thanks for your kind comment!
I especially like the long form of your videos where you go into great detail. I am an ex-broadcast technical guy (and extra class ham) from the 60's through the early part of the 21st century and appreciate your videos very much.
Thanks for you kind feedback Eric!
Thank you for the effort to make these videos with such quality. I really need that isolated probe.
A huge thumbs up to Mr. Carlson for taking the time and effort and his grand old Tektronix scope to fill us in for what this small capacitor in front of the choke (reactance) is for! Back at tech school many moons ago I asked the lecturer what this small value cap was for exactly, I had noted this feature in quite a few amp and radio schematics. His rather annoyed sounding answer was: Cant you see?? Its for quenching RF interference!! Can we get on with the lesson now?? I have built my fair share of amps and power supplies since then, always including this feature, a small HV cap, mostly 0,68 micro, always beleiving it was there to cut diode switching hash especially on the AM broadcast band. Now I know better, thanks to Mr Carlson :-)
P.S. Concerning the Super Probe: Was not there once a little tube Signal tracer by Heathkit with a magic eye in the bottom corner that had a probe with a germanium diode in it which worked in a very similar manner? The model designation eludes me ATM...
Best regards from Germany
Nice, I love how you came to the same conclusion, not one way but with two. Great way to show how things can be done with alternate methods.
Glad to see the end to this project.
What an awesome pair of amps! And after the tweaking, They're even better than before!
I learned so much! Your practical demonstrations, both with the Carlson Super Probe and your older oscilloscope, taught me in ways I’ve never learned from a textbook. What a difference only a half a uF makes!
Interesting! I've seen some designs that feature a capacitor in front of the B+ choke (think it was 2.2uf or so on average) and a lot that do not (mostly Fender Twins of different eras), but didn't know what that was for. Now I do! Thank you again Paul! Please keep the videos coming! You are a great teacher and always can inspire me to both be better at teaching these sorts of things as well as implementing them for projects I wish to tackle as well.
Great photography! Love the sharpness and brightness of the trace on old Tek scopes. Awesome improvement on the amps hum level.
Ken Chorney _ it even gives a nice pleasing effect on the camera at that scan rate.
Wow, that Tek scope trace ... what a beauty.
Is it bad I heard this phrase in Dave Jone's voice when I read it?
@@thomasdavis4253 I think the world would be a better place if all our internal monologues were in Dave's voice.
Wow.....that capacitance lesson was great.....well done. Thanks Paul
Glad you enjoyed Rick!
Mr Carlson..... You are the man. The lab works provided here are top shelve. No dought. Even I can learn here.....
brilliant video. I've learned a lot.
love the clear and bright Tektronix 547 CRT picture
I agree, nothing beats these old scopes for clarity.
Don't understand much of it but still find it interesting to watch and learn something!... Thanx Paul...Rob
Your a wizard... I so enjoy your clear and concise explanation of every detail of what your doing... Thanks again....
My comment vanished! Great job at nailing down that noise Paul. I really enjoyed this. Very nice presentation. I really have to get me an original Carlson's super probe.
Thanks for stopping by Buddy!
Always on the edge of my seat waiting for the next video.
I find this trouble shooting video a valuable resource and a significant step towards my understanding of dampening inductor ringing. I'm amazed that a small cap can make, or break the noise threshold on an amplifier with an LC power supply filter. I appreciate the practical methodology employed in the experimentation process, and will use this process on my own designs.
Just letting you know that I appreciate your educational reviews, as I get to do a lot of cool stuff with your tips and tricks. Each of your videos is more useful than about a quarter semesters worth of circuit classes in my experience. Yeah, thanks
You're very welcome!
Don't understand much of it but still find it interesting to watch and learn something!... Rob.
Snowing.....roads bad....perfect time for a Trouble Shooting Mr. Carlson video!!! :-)
The Carlson superprobe?? My mind boggling, seriously great program. Love valve mono blocks and the transceivers you work on
Thanks Howard!
Great way to head into the weekend.
wonderful, instructive and thorough work you are doing! Thanx!
You did an awesome job on those amps. So few techs have your skill level & valve amps are a bit tricky to work on too.
Just in time for some Friday relaxation \o/
Always enjoy learning and you teach well ,I don't plan on getting into the older tube stuff but I still enjoy learning form it. Thank you.
A tip: Since these videos are so informative and useful for troubleshooting, they ought to be more searchable. If I come across a buzzy amplifier and haven't seen this video (at least not recently), I would suspect that Mr Carlson has the solution, but how to find the right video?
So please add keywords to your video descriptions, even though they might be "spoilers". And think from a noob perspective so don't only mention "Crossover distortion" but also "fixing buzzing tube amplifier" and so on. I think that this will open up your channel to new fans!
Inspiring videos. You have rekindled an undeveloped relationship with electronics from my youth. Now, at age 72, I have the time and the opportunity to continue my journey, not to mention keeping an active mind. During the last 3 years I have learned to speak a foreign language to a reasonable level of proficiency, now I will have to learn the French words for inductors, capacitors, valves, (tubes in your country I think) , current, voltage, impedance, resistance, capacitance, distortion, frequency, phase, etc etc etc. Subscribed and will look at your Patreon pages. Thank you.
Marvellous work, and everything explained with perfect clarity.
Real good video Paul, I never heard a filter choke called a reactor but when I think about it that is what it is...LOL
Thanks for stopping by Bill!
I subscribe to quite a few channels Paul but yours is the only one that I watch all of the videos. Excellent video as always...
Thanks David, glad you are enjoying the video's!
Way back when I was a kid in 1959, I built a 10 Watt amp from scratch using 2 6V6 output tubes, it worked very well. I used an aluminum chassis with the holes punched out with a chassis punch, all done by hand. WA7VQR
Excellent videos. I've always been curious about electronics. And have wanted to build my own tube amp for years.
I love your detailed explanations, and video quality compliments those. Always entertaining and always learning something from you. Thank you!
You're welcome Michelle!
I always love watching your videos because I often learn things that are completely omitted through the modern electronics/electrical engineering university curriculum.
I'm currently a junior in an EET(Electronics Engineering Technology) program at my state's university, and while we recently just covered RL, RC and RLC circuits, they don't really go into why we are learning all of it, or the applications for it.
I hope I can help fill in the holes for you.
Only one word to describe this video,and all of Mr Carlson's other vids...BRILLIANT! Thanks a lot Buddy!! Cheers from Bill in Beautiful Northumbria in the UK.
Thank You for your kind comment Bill!
Thank you for your (again) awesome explanations! 🙌
I love these videos. Learn a ton, and have been doing this for years.
Totally awesome. I’m really enjoying your videos, and learning TONS. Love the super probe. Wow. Your efforts here are very much appreciated!!!
Thank you very much Kenneth!
great video Mr Carlson the buzzing in the choke has always been a real paint for years, it been a balancing act to get rid of it. as you stipulate adding capacitance makes the voltage go up. i am too suprize how may tech forget about the peak voltages. i am building myself a 6V6 stereo amp at the moment. and now the choke issue has been resolved i have 2 PSU in my amp 1 for the left and one for the right and 2 x chokes love your videos keep them coming
Awsume as always never fails to please with his videos !
I loved your videos on the two audio 6-pack amplifiers especially the part about moving the b+ choke around for minimum hum at the speaker. I think an insulated magnetic shield plate might be very helpful. I have used these as a diagnostic tool kind of like you use your Carlson Super Probe capacitive pickup. I particularly enjoyed your fixing of the ringing by testing a variety of capacitors. Nice.
Again great vid Paul, thanks for sharing. I think I need to man up as that arc would have had me jumping and running for cover. I truly love your restoration vids, the equipment you work on is breath taking so much nicer than the modern equivalent. Today I received in the post a lovely little Heathkit Daystrom AG-9U Audio Signal Generator "UK version" fell in love the moment I saw it :-) Again Mr C great vid n keep em coming.
Regards G
This was a very interesting project. I haven't worked on tube stuff since the late 60's and early 70's and most of those repairs were with a Sams photofact with no modifications. It looks like your super probe would still be a usefull tool in my shop with transistor amps
Incredible. So informative. I absolutely love this channel. 😊
Nice explanation, good teaching and high quality video. Thanks.
Great information from a professional. By the way, I sure he hope doesn't live in earthquake country, and , if so, then I truly hope that all of that nice equipment is secured and strapped down so that it does not fall on either him or the floor when a tremor occurs!!
Crumbs - your right! Maybe a computer generated back-drop would be a better plan!
Thumbs up is not strong enough. We need a little SpaceX rocket symbol to click. Outstanding work Paul
Thanks Michael!
Nice job Paul you really are the man Big thumbs up
Thank you for sharing your knowledge. Really appreciate it!
14:44 -Carlson is a badass.
NO ONE else's electronics channel looks and sounds this good! 😲
-Thank you for the tips and tricks as always. 😉
Another great video. I learned a lot today. Thanks for sharing it.
Adding that cap worked out very good. I'm with you, if I found that noise present I would think that some components had been removed at some point.
Hello Mr. Carlsson,
I think your c-l network works like a low-pass filter ..... it makes for the DC voltage almost no resistance, but for the 50/60 heart rest voltage from the rectifier a very big resistance.
thanks for the great video.
73, from Germany
Hi, Walter - yes - the choke is particularly good and necessary in the larger amplifiers as it absorbs the "heart rest" as you put it, (nice expression - I like it!) without losing much overall voltage - evens things out. The capacitor`s storage also helps and takes some of the "strain" out of the chokes action. In the smaller amps, there is usually just a resistor between the caps. which wastes a bit, but works well enough with adequate capacitance - especially after the resistor.
Hi amazing video paul ,thanks for sharing!
Great debugging session! I'm interested in applying this to a 1950's 10W 6L6 Bell amp that has a hum issue.
Very nice Work Mr.Carlson.
Thanks for this amazing episode. Learned a lot. 73 from CT3LG
Great video, Paul. These newer units there's not much space to make any major changes. A fellow on another channel who does homesteading made a wood case to house a water pump and some fittings and valves including a timer. He did a very rough layout to give him ideas for the case size, but he forgot to take into account the pex lines he needed to plumb it. He made it fit, but it got ugly. You have to always think ahead. I'm sure the manufacturer spent much time planning parts layout for functionally as well as Aesthetics.
Awesome Video. I learned a lot. Thank you!!
BTW Paul, by measuring the time constant of the ringing, and then comparing that with an impedance plot of the capacitor, you can nearly eliminate the guess work by aligning the null in the impedance plot of the cap with the ringing of the signal. That said, the beauty of the method you show is in it's simplicity: There are only set positions of capacitors, and measuring them "in circuit" as you did ensures that any other parasitic elements and variations are captured in situ. Love your videos- very practical approach!
Great fix Wizard ..pretty amazing stuff
Thanks for the excellent video's. I have learned so much!
Great job Mr. Carlson ! I'm watching your build of your NEW High Performance dipole for your new lab. Anxious to see how you raise that 30 ft. pole from ground. Hope you cover that in the future. Thanks again for sharing... N3JLR
You're very welcome Richard!
Very Interesting and tutorial way and method how to eliminate the drilling out of a transformer coupled to a voltage regulator circuit.thanks for the very nice method of troubleshooting
You really an Excellent Eng.
I took your comment about bias circuits and applied it to my own troublesome guitar amp kit I built many years ago... Lo and behold one of the cheap bias pots was totally defective! I thought I'd finally figured it out. Amp worked for a few days then blew a mains fuse. After narrowing down some possibilities, I decided to go back from a tube rectifier to solid state and buy some new EL34's just to see if I get some different readings. The last time the mains fuse failed, it seemed to take the pilot light with it though... Now with all tubes and rectifier out, it fails the light bulb limiter test. Have I ruined the power transformer? The amp is no longer mission critical, I'm just going to buy a new Marshall, but it gives me time to strip this thing down and rewire it from scratch and do a better job. Eventually I'd like to use it out, but it's going to have to be absolutely reliable first. What's the best way to confirm the power transformer is definitely ruined?
I need to learn more about this stuff. Like really bad. I learned alot in high school. But seem to have forgotten in the last 20 years
Thank you Mr Carlson for this excellent video and explanation. In the near future would you do a video explaining how you got started in electronics, any certifications and do you own your own company. I enjoy hearing about peoples experiences in electronics.
Great video. I have to make one of your probes. well done.
Amazing skill and video.
Nice video, my dad was a radar tech in the Navy and he mentioned that a swing choke is designed to be driven from the rectifier without a cap and that it acted as a regulator if I am remembering correctly. It would be nice to have a clear discussion about that type of choke.
That`s an interesting account - I`m not qualified to comment, but I have seen amplifier circuits without a pre - choke capacitor. Most of them do seem to have them, though. Mullard used them in the "5-20" but not in the "5-10". That one just used capacitor - resistor - capacitor, both high value, (50uF!) but both amplifiers used limiting resistors after the rectifier - one on each anode out. I think the choke is desirable - especially in large amps, because it (obviously) smooths things out without incurring much voltage loss. As Mr Carlson showed, a relatively small cap, made a lot of difference - and, I would imagine - lessened the high amount of activity in that rather small choke. I`ve probably said too much!
Meant to say "one on each anode IN" ( between trans. and rectifier.)
Very cool modification
Thank you Mr. Carlson
My Pleasure!
That was great mr Carlson, learned so much again,ive had this happen to myself before now,was educational to understand why, you sure make electronics interesting and fun, rearly like your Carlson super probe,think im ready to look into your patreon page and make one of these super probes. Fantastic. You sir should have your own television show! Thanks paul. Lee55
Thanks for your kind comment Lee!
wish you had shown the superprobe output with all capacitors, would have been interesting to hear the difference. fantastic video as always :)
This channel is amazing!
THANKS VERY MUCH FOR THIS VIDEO
Wow. Just wow.
it is so satisfying when you connect the cap to ground and it goes silent!
Man, it sure is nice to see clean fingernails. Your videos are precise, and the clean fingernails add to the bias.
Nice and useful video , thx!
You might want to try swapping the choke leads, reversing the phase of the magnetic radiation. Sometimes this makes a difference in coupling to other elements.
Really enjoyable thank you
Ultra useful. What's great is these are things I'd love to experiment with, but usually just can't due to time so they remain unsolved or solved in a less elegant way. It's fascinating to watch you work through these gremlins. You're super probe is a great idea as well and I really do need to find the time to build one! I'm curious how quiet the choke and amp would have been in it's original position with the cap added? Also, I would have been tempted to use the 2.2uf and drop the bias back to the 180ma range. Xover looked good on the scope with that current setting. Thanks again for all you do!
Again brilliant video ♥ This shows me that the tek guys at HP Agilent really knew their things back in the days. I have some amazing Bolometer and other huge piece of gears made by them for the military I suppose, and indeed lots of them have this (usually 1uf) non polarised caps in front of the filtering choke. I'm not wondering why anymore :D
Great! I'm planning to do a topic on the Bolometer, and its function in test equipment.
This would be awsome Paul ^^
best tech on the tube.
Fantastic video.
Super! Super! Super Great video for me! I learn a lot!
Glad to hear that!
Just checked my late 30s / early 40s push pull AM radio (twin 42 outputs twin 76s for phase inversion) uses choke input off the 80 rectifier tube and has a .22uf 1000v cap in the same place you installed this one. I guess that is there for the same purpose (the choke on that radio is also quiet!)
Yes, Common Knowledge back then... I'm trying to teach these (what seems to be) forgotten ways now. Thanks for your comment!
Great video by the way, no doubt that it will save me a lot of troubleshooting as i'm in the middle of designing and builidng an all GT style MW/SW radio and even in the datasheet for the 5Y4 it doesn't mention ringing when using the tube in choke input configuration. Amazing how once common known things in many old trades become lost into secrecy through "progress." No idea how it's going to perform yet as I haven't sorted out coils / IF stage tranformers but out of the parts boxes i've settled initially with 6SK7's for RF preamp and IF amps, 6SA7, 6SQ7, 6V6GTs for PP and possibly a 6SN7 for phase inversion, oh as well I plan on using your little oscillator take off circuit to run a frequency counter :) The main goal of the build is to make something with low hum, pretty uncharacteristic for a table radio but it's something to do right, especially with some of the SW around here a lot of my radios have more hum than station on the weaker stations.
Mr Carlson's Lab
Is this called a pi filter or is that different (high value capacitor before the reactor)
There will be a value at which the cap resonates with the inductor, and at that point the ringing will be significantly worse than with no cap. You need a value somewhat larger than that, as seen.
Other thing, using a small electrolytic would not be wise because of the very large AC ripple at this point.