Why class AB or B amplifiers dissipate more heat at lower power
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- Опубліковано 23 лип 2024
- You might have heard that class AB or B amplifiers run hotter at lower power. This video explains why with a demonstration.
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Email: johnaudiotech@gmail.com
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The one and only video on UA-cam, revealing class AB amplifier efficiency.
thank you for sharing
Thanks for the great video! Always enjoy your explanations as an avid student of audio electronics. And also to see the occasional snickers! My cat is called neve 😺
Your kitty was hollering for you at 12:30.
Thanks for the video, John!
Great video 🙏, thank you for doing such an amazing work. And congratulations your amplifier design is very near to its theoretical efficiency ❤️👍. Waiting for the next video.
Looks very clean!
Wonderful video
My class a/b amplifier get warmer when i play loud
Sir i hav another question about dco measure at speaker line..
I measure .1mv and max of .24mv at 200mv ramge... setting ...is this normal or abnormal? Thank you sir
Just use Class H amplification, it's a great balance between efficiency, heat, voltage, amperage, and power output.. The RAIL CATCHER! The newer Class H amps. have hardly any crossover distortion..
Sir i have a question....sir which more better type of transistor to used for my my amplifier zsiklai darington or darlington transistor ? which is more better to used..thank you..god bless
Although both can work, the darlington configuration is what I would use.
@@JohnAudioTech sir thank you so much god bless you
Hi John. Love your hands on approach as always. Why was heat dissipation non-linear as output rises? Power supply droop?
The supply is regulated. The dissipated power is a nonlinear function.
I would love to see a good design video of an LC filter for a class D amp, or SMPS output stage.
This suggests that to increase efficiency at lower power you'd want the ability to adjust your voltage rails to suit the required volume levels.
A variable voltage rail would be an interesting feature for an amplifier that has to do multiple duty as both an easy listening amp and a party amp.
You just described class G for linear amplifiers. It uses a low and high voltage rail and switches automatically when more voltage is needed.
@@JohnAudioTech
I was thinking more in terms of a manual "eco" switch where you'd adjust the voltage regulation down to match the low power operation rather than multiple rails and automatic switching.
While typically you use a variable resistor for adjusting regulation IC's output, you can also just switch to preset resistors for matching the positive and negative rails.
If you're already regulating the supply, it's just a couple of resistors and a switch rather than needing a more complex multi rail power design.
I'm sure that there'll be other considerations due to gain etc, but they shouldn't be too difficult to compensate for.
How about Class A amp? Still more heat dissipation at idle compare with full output?
If it's pure class a (single ended class A), the dissipation is at max when idle. Which is not the case with class B(AB) that are max at around 60% instead of at idle.
Great video. For future you may want to cover Class G.
I don't know if I can agree to all this ..... I've used many amplifiers big ones 1Kw to 6Watt and I've always noticed how hot the heat sinks are when driven hard compared with how much cooler they become at half power output ....
As mentioned in the video, music has a lower average power than a sine wave. At high volume, music can put the amplifier in higher dissipation than a sine wave a max level before clipping. It depends on the type of music and the speaker reactance.
@@JohnAudioTech ok ... that does make sense now ... I did overlook sine wave power considerations versus music power ... quite a big difference...😀
I'd be interested in partnering to make and sell boards. I can also design the boards.
I'm in the process of making a new website, a blog and small store for some of my own boards.
Let me know.
I plan to make a video about the board design criteria in a couple months. If you're in the US and are willing to distribute to most locations in the world, I'd appreciate the help.
I just noticed your address in the video details, I'm going to shoot you a quick email.
Interesting and well presented explanation, as always. And Snickers commentary, though relevant, seemed to be slightly off point. Might have been my interpretation of feline dialect, so take that with the proverbial grain of salt. Lol.
Have a happy, safe, and most of all, meaningful Christmas. My best to you, Snickers, and your whole family.
Nice sir.i am indian.sir piliz send pdf.
Meow!
Back in the day the FTC rating where true and proper today it's china lying shit spec. The only spec is 20-20khz @ say.05% THD, RMS power, NOT 1khz @10% THD peak to peak then x 3.
Oh god. It has nothing to do with China.