All You Need To Know About AMPLIFIERS To Fix Stuff - A Beginners Guide To Audio Amplifier Repair
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- čas přidán 6. 07. 2024
- NOTE TO BEGINNERS This video is suitable for anyone with at least a basic knowledge of electronic components, particularly Transistors. If I covers topics here that you are not familiar with I strongly recommend you watch my other videos in the 'All You Need To Know About'.. series first. In particular 'All You Need To Know About Transistors To Fix Stuff'
You will find the other videos in this series here:
• The ALL YOU NEED TO KN...
Mentioned in this video - No oscilloscope? No problem!
You can use a pair of amplified PC speakers or similar to aid in fault finding amplifiers
• How to test GPU / CPU ...
(Northern Soul) Music in this video
David And The Giants - Ten Miles High
Hill Audio DX3000 Schematic and Service Manual
www.badcaps.net/forum/showthr...
CHAPTERS
00:00:00 Introduction
00:08:10 Amplifier Classes
00:10:33 Class A Amplifiers
00:17:34 Class B Amplifiers
00:24:52 Class A/B Amplifiers
00:29:47 Class G & Class H Amplifiers
00:42:10 Bridge Mode
00:45:40 Class D Amplifiers
00:50:21 Test Equipment
1:04:38 What Goes Wrong
01:24:09 Practical Example
01:43:33 Epilogue
Learn Electronics Repair #236
I work in collaboration with:
The Electronics Channel (with Carlos and Detlef)
/ @theelectronicschannel
Gran Canaria Uncovered
/ @grancanariauncovered (with Detlef and Julie. Not electronics related)
Det Builds Stuff - / @detbuildsstuff8128 (Detlef)
Retro Upgrade - / @retroupgrade (Carlos)
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Equipment used in my videos. These are affiliate links, you pay the normal price and I make a small commission.
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Thank you
Richard
A couple of points: As a few people noticed I mixed up the terms peak voltage and peak-to-peak voltage a few times in this video. I do know the difference it was just me having a bad day 🤐. If you noticed the mistakes then I hope you can skip over that and relax in the knowledge that you are correct 😉
Another topic that I did not mention, because I was looking at a PA amplifier, but is very relevant to Amplifier repair especially when it comes to the 'home stereo' type amplifiers from the 80s and 90s (but other decades too). If you have one or more these symptoms:
* an amplifier with the voltage rails present but no sound output on one or both channels
* intermittent audio on one channel or both
*it works on some audio sources but not others
* one channel lower volume than the other (or changing volume by itself)
*crackling, popping or other (often intermittent) noise on one channel or both
Then the most likely cause is the input select, mute and/or speaker select switches that are causing the problem. Usually these are multi pole rotary or push button type switches and the internal contact become tarnished with age. In my experience the only way to fix this (reliably) is to remove the switches from the PCB, carefully dismantle them, and clean the contacts. Usually replacements are not an available option and this becomes more a restoration job than a repair job.
yeah I noticed but w/e it easily corrected in our heads. Are you sure it wasn't a secret test ? hehehe. Thanks
It happens. Don't sweat it.
I´m strongly with Scott Grammer on this: We all make mistakes man. But there aren´t many people in the world who can do what you can. Be proud of your skills, try to learn from mistakes - the only real mistake is to never even have tried, be gentle with yourself.
I believe you're able to add corrections on videos with on-screen text input.. just food for thought, although it then just becomes a tedious task to satisfy the needy and greedy folks that feel their balls tickled with a feather anytime they hear such horrendous inaccuracies and MUST ASK FOR THE MANAGER lol just messing
@@BigRedGevo😂 too true
I have been repairing audio equipment for 30 years in a shop and at home and I feel like you did a great job on the explanation in your video and think it's amazing that you're passing that skill on to other people
Where have all your kind gone youre impossible to find. I have ten things need fixed and just going to have to learn how on the weekends cos nobody in ireland seems to do it any more. No harm to earn we will all need a ham radio when the apocalypse really gets into swing.
Zombies don’t use radios, so ….. little use.😊
We love the way how you approach electronics repair - no fluff but direct to the core of it. Another great video - thanks for uploading.
Cheers 😀
I really don't think you can find a better guide to audio amplifier repair on CZcams.
Thank You! 😀
Agree, I subbed immediately!
Indeed 👏🏾💯
3 years of EE studies and then one hour on CZcams
Uncle doug joined since 2010 check him out
Excellent. The effort that this man is putting into his videos is excellent. In today's world time is the best thing that you can donate and this man with all his experience and knowledge has given us exactly that. Let's all appreciate that. Thank you, sir, you made my day (or days).
What a great video, been repairing electronics for 30+ years. I always appreciate anyone that can explain the difference between the different classes of amps. There is just so much to learn when repairing audio amps. Even after 30 years I’m still learning. To all you newbies.. never give up and learn all you can!
Peace out.
If my electronics teacher back in the days was anything like you, I might have actually finished the semester! I really enjoy how you go about this in a most practical manner - Of course, knowing the inner workings of semiconductors down to the atomic level can be interesting and all, but at the end of the day does little to nothing to help you breathe life back into some dead/crippled apparatus. Keep up the good work!
Top
I've been a similar situation, Back in 93 I wanted a HAM Radio License, but the guy teaching the course preparing you for the Exam, made it unbearable, I learned nothing, didn't get the license, cost a small fortune.
@@DaddyPsyMonn Many people have loads of technical knowledge but are clueless about how to teach it to others. Unfortunately, many become "teachers" and "professors". This gentleman is very adept at passing on his knowledge. I am very happy to have found his channel.
You are indeed an amazing teacher. I applaude and thank you for the great deal of effort and dedication you put into producing these valuable videos. Thank you so much
Once again, every minute of watching this video was worth it. Now I know the working principles of amplifiers. Thank you for dedication on teaching very clearly.
Thank you - I hope you can now start repairing them 🙂
Your explanation along with your hand-drawn circuits opened my eyes. Thank you for your time and knowledge.
You are welcome
Absolutely brilliant video. You have managed to clearly describe how all of these amplifiers work in such a way that anyone with a little concentration and some basic familiarity with electronic components can grasp it all. Many thanks !
Thank-you for spending a large investment of your time producing this video. I've watched it all and have learned a massive amount from it. I love tinkering with 'dead' amps from the 80's / 90's and your tutorage is just spot on! Thanks again :)
It is true that my more recent videos are taking more time to make (and I also think they are of better quality and certainly more ambitious) but as it so happens I really enjoy making them, it's more like a hobby than a job to me so just sit back and enjoy 😉
IMAGINE , I watched this vid with a larger some kitkats and a packet of cheese an onion crisps (Tesco multi packs) for an hour and 25minutes ,then saw you SEE the fault , sort it out and then play a Dave and the giants number ...... I enjoyed every bloody minute of it . you legend you!!!!!
Thanks for taking the time to explain in detail how these amps work.
Thank you for this most detailed description of the various classes of amplifiers, how they work and common faults. Amps have been a mystery to me for decades. I used to be in various bands and built some of our own equipment. This helped me in understanding & diagnosing an old Playmaster 300W Subwoofer amplifier from Electronics Australia Magazine May 1995. It exhibited the symptoms you described precisely. It's a pity these videos were not available at that time, they could have helped me fix it then rather than buying/building another one.
I think the transformer used in the video to invert the audio signal is a stroke of genius. It could probably have been done using op amps/ transistors, but I'm sure they had their reasons for going down this path.
I have learned so much from this! Thanks for taking the time and effort with the various classes of amps and operating principles into something I could follow. You are an absolute star my friend!
I repair 50 to 100 amps a year and I still picked up a handy tip or two. Thanks! Subscribed!
What a great teacher a great sense of humor as well you explain theory trouble shooting technics what to look for and how to go about it OUT-Standing
been looking for a video just like this for weeks now, this is amazing. You explain everything in a way that makes understanding it intuitive. Thank you legend.
excellent video Richard, it really helps when you explain how the circuit works. When you know how it works you can fix it. This truly is the best channel on CZcams for learning electronic repairs, because most channels are just watch me repair type videos.
I've learnt so much from you Richard a big thank you for sharing your knowledge and experience.
You are a talented teacher! This was a great video and I especially loved how you went through the design differences between the different classes of amplifiers. I learned a lot in terms of troubleshooting that I didn't know before and understanding how the different classes are designed I can see is essential to being able to troubleshoot effectively. Well done! Excellent video, and THANK YOU!
Brilliant! Thank you for doing this! Theory + live exercise all in one video. Learned and thoroughly enjoyed!
Thank you so much. I have been in electronics repair for 45 years. DC coupled circuits are sometimes very difficult to repair. This video is very good for anyone who is just starting to get into audio amplifier repair and a good refresher course for us old timers as well.
Somehow I fell asleep for 12 hrs with this video on repeat. I can't help the overwhelming sensation of wanting to disassemble broken amps and do things I didn't know were possible yesterday.
subliminal amping
Nice video. I have been in the repair biz for many years and learned a lot from this presentation. Thank you.
the best electronics channel without question. looking forward to all you need to know about mosfet video
Oh, it's coming.. you won't have to wait too long 😉
Great basic guide. Looking for something like this for 2+ years......explaned everything i have been trying to understand about how amplifyers work and how to fix them...
Thank you sir.....👏👌
You are welcome
Awesome video, great information, really well presented. Just another day in the shop for you, Gold standard education for us! Thank you
Your a very clever man, years working on the bench and knowledge all makes a great teacher. Cheers mate
What a great channel! I've been repairing kit like this for decades, but this video has reminded me that every day is still a school day - some handy tips there, thankyou! Talking of a belt & braces approach to testing, I like to stick a voltmeter across the speaker outputs of an unknown amp before connecting the speakers, just in case there's a full 70V just waiting to fry my test speaker! ;)
Outstanding content regarding amplifier topology and then fault finding using that knowledge in one video. A master class, really, in a "short" 1hr 45min. I have a blown guitar amp and now feel like I know how to approach fixing it. Thanks!
Oh for sure I know how to make 'short' videos LOL. Great to see you enjoyed it 😁Good luck with your repair, let us know how it goes.
Also can I suggest the LER discord server - it is a great place to post and discuss your own repair jobs with others
Learn Electronics Repair is now on Discord! Come and join the fun, it's free.
discord.gg/vam6YC8vwU
I'm not into electronics, but I'm currently shopping for a new system, and this was quite enlightening! Thank you very much, sir.
You are a great teacher. Enjoyed this a lot!
Thank you, so good to hear the wealth of information you have. Love the explanation of the various classes.
Thank you for taking the time to share 🤗💖💯👏👏👏👏👏
Just watched this from end to end. Absolutely fantastic explanation. Thank you for sharing.
Great job... subscribed. Just starting my 1st solid state amp project, learned a good deal of what I need to get started. Thank you!
Another wonderfully clear and concise video, Richard. Thank you so much for making and posting these. I thoroughly enjoyed that one.
Hey that's great to see you enjoyed it 🙂 Of course I only do concise at 1hr 45 mins LOL
Thank you for producing this video and series. Excellent presentation of the types of amplifiers.
Thank you Richard for an excellent presentation. I thoroughly enjoyed the learning experience.
My favorite topic. I used to build custom amps in the 80's using 2N3055 transistors. Philips was a tried and tested circuit at the time.
You covered a lot of material and I think it's the best video ever about and the repair of amplifiers. I like your video's very much.
Wow thank you! There is some stiff competition from some very good creators out there in YT land. 😊
This Guy is a fecking legend! I have a basic grasp with electronics, but the amount of useful info I have taken in just by watching 3 of his videos is crazy.
Excellent work. Thank you.
This video and explanation really came in at the right time for me. It just happened that I have an amplifier on the bench to repair. No audio out on the speaker terminals. The power rail is good. I have schematics but was a bit of researching without realling knowing where to look at. With your video I'll probably diagnose it in a more structured way. By the way, it is an AKAI AA-1135, back from 1980.
Hi Chris. good luck with your repair, I hope this video helps you.
I had a quick look at the service manual. With an amplifier of that vintage, bad contacts in the front panel input/signal selector switches is a very very common problem so keep that in mind 😉
Cannot thank you enough for this generous gift of time and knowledge.
Back in to 70s, we built what’s now known as “bridge” amps, and called them “reverse phase double push pull”.
For the class D amps, we called the sampling “quantizing, or A/D and D/A, and or “codecs/processing” .. very common now with digital communications in use today.
Ended up answering my own question from my comment yesterday, the topology Peavey used in mkiii’s/mkiv’s etc is “quasi-complimentary”, and they did it due to high power NPN’s being better/more reliable at the time. A video on how these work would be a great addition to this series! Thanks for all the amazing videos btw!
I have to say I've never got so perfect lesson about amps philosophy in 1,5 hour. This was invaluable. You should write a books - you maybe would be rich person. I am just renovating DENON 525R amp from 80-ies. And this gave me nice basics to understand what I am doing now and for what I should look for. Thanks a lot and now I have listen next movie. Perfect lesson. Thx. Marek/Poland
Thanks Richard for expanding my electronic knowledge, my brain 🧠is a bit fuller now, cheers.
The best AMP explanation EVER !
We have the worst instructors (teachers) in the United States. We spend more than any other country and our children are more ignorant than ever. THIS guy has just schooled every teacher
out there. Amazing presentation... and how you anticipate the questions while I am formulating them is absolutely amazing.
We have teachers that like to make things seem complex to fuel their own ego's. It's a hugely rampant problem in the American public education system. It doesn't pay good, so it tends to attract people who never had the power they wanted over other kids when they were in school, and it attracts people who are addicted to making themselves feel intelligent. Very rarely anymore does it attract anyone who actually wants to help a child learn something. Most high school teachers hate the children they teach because by the time theyre that age, thanks to all the other crappy teachers, and the crappy parents, they are unteachable overly aggressive baboons anymore. Every single teacher i had growing up that wasn't garbage got out already, and aren't going back.
Thank you so much for this very informative video! I learned more from this video than some classes I've taken.
Thank you. That cleared up a few grey areas for me.
Interesting amplifier for sure, especially with the TDA20XX series pre-amp ICs.
Thank you so much for your master class.
Would it be possible to have a video about matching transistors and HFE?
I think that calibration and gain in amplifiers would also be interesting.
You are an amazing teacher!
Very practically oriented video, liked the way you imparted knowledge.
Fantastic video. Well presented and very informative.👍🏻
Top notch mate! I may go back to try repairing again thanks to you!!❤
Excellent and clear, these class distinctions ! 😀👍😎
You're my favorite professor on youtube university.
Thank you so much!!! Thanks for sharing your big knowlege with so simple way!
Superb descriptive info appreciated
Excellent video , thank you and God bless you....
Very good explanation and demonstration
Great video! It get me veeery much years ago in memory!:)
I used to run a hill dx3000 was an absolute beast!! Hill audio sounded lovely and used old skool mofets. Lovely warm sound 😊
Thank you. This was an excellent lesson.
Love the set and the lesson. Thanks
Outstanding stuff, just what i needed.
Such a great channel! Subscribed!
You are fantastic. Love your video. I usually get bored and never watch them till the end but your video was so entertaining with practical information that I watch it till the end. Please post more videos. thanks!
Hi friend thanks for the informative video and this is the best layout for amplifier classes I have seen so far. Thanks for taking the time to do all the videos, it is much appreciated
Thanks a lot for putting together this video and going so much into all the details - I learned things and it was very pleasant to watch! :)
Wow I watched your psu video this morning and now came back to see if you have any amplifier vids, low and behold you just posted one!
I like to listen to subscribers and several asked for it since the 'AYNTK about Transistors' video few days ago, so I took the first opportunity I could. I hope you enjoyed it. 🙂
great vid like always thanks for sharing
My son has vintage Akai gear .
AA1175 dual Mono amp.
Very nice video
Congratulations, Thank you and appreciate your effort. Greetings to you from Turkey .
great job in explaining it
Very well laid out video..
Thanks for the nice overview!
Just found your channel. Great video! Looking forward to learning more about diagnostics and repair.
Great video. What a class. Subscribed 3 videos ago. This is the kind of information that I seat and watch until the end.
Welcome aboard Rui 😀
@@LearnElectronicsRepair pleased to know you
Thank you sir ...this stuff is GREAT . Certainly helps clear the cobwebs from this old noggin !!!
Amazing ! Great video , the best i see until today , thanks !!!
What a great job you do explaining these things. Thank you! Like I said on one of your other videos is you should try to explain how to build a VFD from single to 3 phase electric for us Americans with only single. I think that video would do great!
Excellent tutorial on power amps.
Thanks Malcolm
Me lad I thank you for doing a super job on how the different class of amps are designed 👍
Only if my teacher in class was like you I would have been a better tech and would have made my electronic career much easier over all
My hat goes off to you
You are the best keep up the super work.
Ot takes time to do these videos I thank you from the bottom of my heart ❤
Thank you again .
Cheers 🍻
Great video - thank you
That is one big assed amplifier... thanks for sharing your wealth of knowledge and the great video. 😀
Great video Thanks
Thank you for this content. Great video.
very good teacher , i didnt get everything the first time , but ill watch the vid again in couple days .
Very good explanation
Wow. A great video. Thanks for your work, i have a amplifier to repair. Congrats for 23k subs btw
I very much appreciate and enjoyed that..Great thanks 😊
Great job. The best channel i found on yt.
fantastic video :) your fault finding skills are amazing :)
I wonder how I came to this side of the internet? Actually learning a bunch. Congratulations from Portugal 🇵🇹
Thank.You.for.sharing.your.troubleshooting.skills.with.us!
cool video man. thanks for your info.