Discrete audio amplifier project PT13 FIRST POWER UP and diagnostics

[@andymouse]

I've been watching all the series, and will do several times, but can't believe I missed this one till now ! realy think this amp has soul...cheers.

[@reginaldmorton2162]

According to Mr. Pass, all stages should be tested for conductivity/ polarity before moving on to the next stage in assembly. This is to cut down on trouble-shooting and mistakes made by all technicians regardless of their experience. Great step by step, I will be donating!. Thanks

[@1959Berre]

A small step for John but a giant leap for mankind. Just kidding. Well done John. Really appreciate you're showing the mistakes. So we can learn from it.

[@Markoul11]

Congratualtions! Just people to appreciate how hard these things can be, made up from the design to finish. Thank you for this wonderful project series.

[@diy-speaker]

Congrats from Russia to you! I'm so happy for you. That feeling when something you have made actually work is truly amazing and worth every hour of your life that you have spent with it.

[@markbuxton2368]

Theres thousands of defuct amps out there just waiting for a JAT module to bring them back to life. Great work!

[@1pcfred]

Congratulations on getting your amp powered up.

[@Nobody-NoOne]

Very cool. When you got music to play, I have felt what you felt before :) I built a few projects, and nice to see someone gets the same gremlins, then tada, success ! Nice work man.

[@SuburbanDon]

Cool. I'll commit to,buying 1 or 2. This is really exciting to me.

[@iblesbosuok]

Amazingly it sounds great. And your meow gives additional warmness. Cheers from Indonesia

[@steveswan5714]

Great result John but old age don't come alone lol how many times I missed solDering something when building projects the debugging can take longer than the build !

[@bixy9347]

You did it!! Congratulations John.

[@Tommyinoz1971]

Hi John, this is your neigbhour and it's nice to know that you have your amp working. Now please turn it down unless you're playing ACDC.

[@MrAlFuture]

Wonderful to see the progress and your troubleshooting methods, John. Thanks!

[@joohop]

Nice Work Earthling Been Looking Forward To This For A While

[@cac2244]

Appreciate to see that it happens to even the best, that you power up and "nothing!"... Great series, thanks John.

[@briccardo100]

Congratualtions! From Italy , Thanks.

[@jamespalmer7629]

A cold one has been had! can't wait for the finished product, I would love to add a jfet preamp and tone controls for a guitar amp!

[@Marco.SalaMessom]

Congratulations From Brazil!!! I am here since the beginning. It's so good to see It working. I Will by It for shure!

[@twotone3070]

Well done John.

[@HimanshuSharma-dm8ol]

Waiting for its full performance ❤

[@BrucesWorldofStuff]

Wow, John... I was rooting for you! I is so great when it works warts and all. Don't feel bad I have left connections off myself, so don't feel bad about it. I could be talked into buying a board or two, if and when that happens... Tes I have tons of my own to work on but that is not the point, it's "Johns" board... LOL Congratulations!!!!!!!

[@JohnAudioTech]

Thanks Bruce!

[@hellhound-si5oz]

And be really nice to see your version of it in SMD forum

[@peteb2]

i can always use a discrete 'utility' amp at my hobby bench that contains parts that are readily available, that i'm familiar with and its workings (performs well) plus all the data about it is available....(if i have a woopsee and do something bad to it), would be just about the best thing. My last waste of money was an aliexpress thing that suddenly let smoke out when it was just sitting doing nothing except powered on and there are no spares by the look. This amp of yours looks like it would fit the bill for my needs!

[@fredfabris7187]

On start up I like to watch the voltage drop across the emitter resistors for proof of idle current

[@jean4756]

Very very good boy. Perfect amplifier nice work incrível. O trabalho foi bem efetuado, bela engenharia. Parabéns 🙋🙌☝👌👍😎✌👏👏👏

[@terencekaye9948]

IIIIIIIIIIIIIIIIIIIIIIIIIT's Aliiiiiiiiiiiiiiiiiiiiiiiive,,, Yay,, Way to go John,, Nice work,,, Been on the edge of my chair for quite a while :)

[@vicentecortez8636]

Wow!!!

[@jaredgray7872]

Congratulations!! So great to get to this point! Do you think you could do a little bit on how you setup your power supply and connect it for +- voltage?

[@demoncloud6147]

Wow ! just wow

[@adrongarretson6195]

I am very interested in acquiring one of those amplifier boards if and when you make hits of them let me know I would definitely buy one and assemble it

[@gamiwv]

I have to propose to have a look at an article of "WIRELESS WOLD, OCTOBER 1979 by B. J. Codd" (you see I'm not young at all). It is a nice (fair) design for that century 😁 but without an active feedback and zeroing output dc offset

[@ejlockpix]

Nice work John. If you decide to make kits I'll definitely buy one or two. You could probably set something up on eBay or something if you needed to. Also if you need any help or suggestions with board layout let me know. EasyEDA is a great free tool. They don't pay me to say that I'm just a satisfied user. 😎

[@JohnAudioTech]

Thanks! I will check out EasyEDA once I get the design tested and confirmed.

[@johnyang799]

I have access to altium 19 and have tried eagle and kicad. Tbh easyeda is really well built and stable. For these transistors capacitors simple components based project, just can't go wrong.

[@johnyang799]

@@JohnAudioTech BTW what about darington vas and output inclusive feedback discussed in the Douglas' book?

[@resistorsarefutile3233]

This would be also be good for powered speakers.

[@joohop]

Definitely

[@lalbabugupta8380]

Sir, i am in confusion please help.. Which one is better tpa3110 or tpa3118? Which one has better bass I will power them from 3 18650 lithium battery Which one has more powerful and clear sound? Which one worth every penny

[@anindyamitra5091]

Congratulations!! I was waiting for this video, finally it's here, thank you! I have a question, can I replace the LED with transistor based current limiter or a zener voltage regulator?

[@gamiwv]

Hi there. I believe that zener is very noisy (at first) and secondly they don't have a "clear knee" voltage. So.... LED from the other side have a very "clean" break voltage that doesn't "drift" too much - as current holds low

[@anindyamitra5091]

@@gamiwv , ok, I got it, thanks!

[@anindyamitra5091]

Do you have any opinion on jumper connections in analog circuit boards? Does it affect the quality, or anything like that? Or dozens of jumpers on a board is absolutely fine?

[@ivanrodionov9724]

as long as the jumpers are not too long and dont twist too much it shouldnt be a big deal if your working with frequencies that are say in the audio range.

[@johnyang799]

That depends on what node it is. Normally shouldn't put too many of them. But unless it's a node carrying a lot of current it's fine.

[@johnyang799]

Oh if you are working with feedback circuit it's not a good idea either.

[@anindyamitra5091]

@@johnyang799 , what do you mean by feedback circuit?

[@johnyang799]

@@anindyamitra5091Negative feedback path, sometimes it's not simple resistor or connection. Can be a relatively complex network. And you don't want jumpers in there. Because negative feedback actually runs at mega Hertz range. Parasitic impedance may cause instability.

[@ruikazane5123]

JohnAudioTech is not sponsored by Dixon pencil in any way whatsoever.

[@snaprollinpitts]

Fanfreaking Tastic!!! great video John!!! I had one board I worked on for about a week, and that was the end of my using perf boards!!!!!! Now I make my own boards, easy enough to do,want me to make one for you? mike

[@JohnAudioTech]

Hi Mike! I have tests and tweaking to do with this one and then I'll design boards. If I run into so much rework, I might need a board made. I found another mistake on this one after the video.

[@datech6274]

Hello Mike, I will like to make PCBs too. Can you help me with the cheapest means to attain my goal?

[@MrBrymstond]

I don't care what they said about you, I had total faith in you and when I make a blunder I always think up a great excuse to make it the fault of something important like the president called me and I had to save the world. Now what size heatsink and power supply is suggested? Thanks for all the hard work.

[@vishnuvinod1896]

Please add your new videos to your playlist ☺☺☺👍👍👍

[@amitghosh6966]

Please make a video on 10 watts push pull transistor audio amplifier without transformer coupling

[@DAVIDGREGORYKERR]

what about a dual channel 2x BD131's driven via a BC212L, if you are wondering what I am going on about then Google 5W Class A amp just a simple class A amp that would be easy to debug if something goes wrong.

[@davidb.7223]

I''m interested.

[@joohop]

Brilliant Stuff Lad how much do you reckon just one Mono Kit will be cost wise ?

[@JohnAudioTech]

Not sure on the cost until I get the bill of materials finalized. I hope I can keep it under $50.

[@joohop]

Nice one Buddy

[@olipito]

Yippee!!!!

[@iceberg789]

i was thinking, may be you could replace the aplifying Q9 with an AC187.....

[@dibyamartandasamanta583]

I will prefer AC125 or 2N404 , Germanium transistor gives vaccum tube sound like feeling ,very warm and engaging yet sharp & crystal clear But they are hard to get . I asked A engineer of Ahuja , they said they get it from NJS

[@talhaashraf6459]

Can you please properly show the schematic of this audio amplifier?

[@PeteVanDemark]

Reserve one for me!

[@jstro-hobbytech]

I'm trying to convince the wife to let me get that psu but it's over 400cad

[@johnyang799]

Hahahahaha same mistake as the old breadboard amplifier

[@johnyang799]

kzbin.info/www/bejne/l5K2aIduj7-WiMk

[@johnyang799]

Also would you add output inclusive compensation? That improves a lot by adding almost nothing. What about darlington VAS? It's really not adding much either.

[@JelckedeBoer]

Just admit it. Snickers fixed the amp for you.

[@aljivenalejo3904]

let me guesses looks like rod elliot design

[@JohnAudioTech]

More based on design I learned from Bob Cordell and Rod Self. Rod's 60w amp is a simpler design but still a good amp.

[@aljivenalejo3904]

@@JohnAudioTech yeah i knew frm the first because almost all the amp i see and me i design too dont used biasing pot anymore i always used constant stable biaasing resistor and for sure