Class A operation of the JAT501 amplifier - will it work?

[@wastingtime9152]

Great explanation on class A , AB operation. Happy to see Snickers approved.

[@isoguy.]

I've heard of push pull amplifiers before but have never heard it so clearly explained in terms that mere mortals such as I could easily understand. Thank you for sharing this awesome vid. 👍👍👍👍👍 Support right to repair legislation in your state..

[@ipissed]

I went ahead and nominated Snickers at the Academy Awards for best actor, non- speaking in an educational/instructional program. You should be getting that Oscar in a few weeks. No problem. It might be stressful with all the autographs and looky loos for a while, but Snickers deserves the recognition. 😽

[@lightbit553]

Class A is good for heating in winter.

[@demoncloud6147]

2 weeks ago I used my notebook as a foot heater inside my blanket. Works well with an AAA games running

[@JohnMcCoy]

Nice explanation of class AB vs. class A operation...

[@demoncloud6147]

Knew a bit about class A, B. D amps before but after watching this video from JAT guru, I have a solid concept. Thank you, Snicker's human

[@cognitivedissonancer]

Thank you, John, for another wonderful video. As always, your explanations are so easy to understand and I always finish the video with a big smile ^^

[@Stelios.Posantzis]

That's a great demonstration. I always wondered whether a class AB amplifier would survive the conversion to class A and you've demonstrated successfully that it can, provided the supply voltage is lowered - a simple solution! On the point of low efficiency of class A amplifiers: the same exact argument can be made for the majority of loudspeakers. In fact, for loudspeakers the situation is even worse as most of them are less than 1% efficient in converting electrical energy into acoustical energy. So to turn the argument on it's head: don't worry about amplifier efficiency, worry about loudspeaker efficiency! (Which is why most class A amplifier owners have really efficient loudspeakers). Some back of the envelope calculations: - 0.5W acoustical output @1% loudspeaker efficiency = 50W AB amp output @ 50% = 100W - 0.5W acoustical output @4% loudspeaker efficiency = 12.5W A amp output @ 15% = 83.3W so you can have the same output for the same power consumption. It just depends on how you go about it and what you want to do. We can even factor in the extra cost of building the class A amp and highly efficient speakers on another back-of-a-napkin calculation!

[@bixy9347]

Great diagram, you’ve got a knack for drawing easily understood pictures. Thanks

[@MrDunk66]

Thanks. New knowledge for me.

[@gazzaboo8461]

Thumbs up for added Snickers!

[@1pcfred]

Audio is not always a practical pursuit for many. In fact it is one area where folks tend to get very unreasonable about things.

[@marcusm5127]

It's the point where feelings meet physics. Can't go wrong.

[@イエンスヨハンセン]

...that said, I do like class A for some things. The first amp I ever designed myself has the smallest number of components I could figure out coupled to a single mosfet output. I have yet to work out the exact power it’ll put out, but I reckon 2W into 8o at the outside. It drives my 91dB speakers at comfortable listening levels. And it drives my circa 1980 Stax Lambdas beautifully. I guess what I’m saying is, do you need 60W?

[@JohnAudioTech]

Yes, you can make very simple amplifier in class A. It depends on your needs as to power requirements. I used to use a 2 watt amp but found I needed a little more power.

[@Automationacademytv]

Thanks for sharing your knowledge very informative, it inspired me to focus more making electrical video

[@cittroman]

You can also do as for example Yamaha did i some of its amps. Run it with normal bias in standard AB mode but you could also raise the bias by a button to have class A mode up to 5-10W, it's very seldom you play above 10w in normal listening.

[@bugdrvr]

My Yamaha A-1000 is one of those. I honestly can't tell much (if any) difference with it running in A except it gets a LOT hotter. I just leave it off as it's biased pretty high in AB anyway and I don't need to cook any eggs off it's top cover.

[@1959Berre]

Nice.

[@steveswan5714]

Snickers know what life is all about 😂

[@tebbi67]

on minute 9:50 there is no bridge on the supply from plus to minus! can it work without?

[@steveswan5714]

Thanks John great explanation of classes 👍 but I think class A should be outlawed to save the environment 😂

[@Stelios.Posantzis]

See my comment above, but, yeah, mindless energy wastage should be outlawed - for example having the air-conditioning on with open windows etc.

[@cocosloan3748]

The cat is BEAUTIFUL

[@scottmiller3025]

How do u know what ur DC bias adjustment should be?

[@ubergeeknz]

Came for the Electronics. Stayed for the Snickers 😻

[@AMPLIFICADORCOMTRANSFORMADOR]

very good.

[@andymouse]

Which mode of operation preferred in high end audio please? have you done a vid on that..gonna get into your back catalogue soon so sorry about dumb questions !...cheers.

[@JohnAudioTech]

A class AB amplifier of good design is all I need.

[@andymouse]

@@JohnAudioTech Oh, thanks for your response, I have just found you and am doing a bit of bingeing ! I have a few questions for later on (hope you don't mind) love your teaching style.cheers !

[@mickblackmore290]

High John, This might be off topic. How do you use 2 different power supply's at the same time? I have tried this using different supply's and it just never works. I was trying your current limiter just one for-instance

[@JohnAudioTech]

Depends on how your using it. If both supply negative terminals are are earth referenced and you try to make a dual rail supply as I did in the video, you could end up shorting the negative side supply out.

[@Nono-hk3is]

Hi Snickers!! 💜

[@dibyamartandasamanta583]

will you sell pcb?

[@bradcfi2]

Is there such a thing as RMS Watts? From an add. "The two tubes in this amplifier generate 40 RMS watts per channel of distortion-free signal, adding punch and clarity to high bit-rate MP3s, Apple Lossless, or CD-quality audio played wirelessly from an iPhone, iPad, iPod touch, or Android phone."

[@JohnAudioTech]

You are smart to ask this question. Watts RMS is an invalid term and is never found in any electrical engineering book. The proper term is continuous average power. I made a video about watts RMS a while ago.

[@scottmiller3025]

Man I got to get a new scope. I can't do cool things with my 60's model tube scope.

[@listerine-pr5lt]

What about 16 Ohm speaker Load? Are the class A Amp still non practical?

[@JohnAudioTech]

A 16 Ohm load would lower the current requirement but the ratio of wasted power to output power would still be about the same.

[@DAVIDGREGORYKERR]

Just Google 5W Class A amplifier which uses 1xBC212L and 2xBD131's should give you what you want or replace the BC212L with 3x BC182L transistors in a long tailed pair and the positive side pulling the base of the bottom BD131 to ground the feedback is from the output to the inverting side via a 470K resistor.

[@SuburbanDon]

Damn. I can't say, "She's gonna blow !!!."

[@adammorris3082]

Thanks - but your supposed to listen to class A with a critical ear and not just judge with a technical eye - Ever since first hearing a pair of high power Class A Avondale modules driven by a toroid supply I've thought class A's the way to go for a good solid state sound, And it's cold here in England most of the time so the extra heat's welcome. lol. All the best.

[@bradcfi2]

Great cat!

[@shantk7378]

17:00!!!

[@SambalpuriSarkaar]

ACHHA LAGHA

[@stephanc7192]

I don't like the Class A idea!