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Benefits of Class-G and Class-H Boost in Audio Amplifiers [pdf]

  • 48 points
  • 12 days ago

  • @type0
  • Created a post

Benefits of Class-G and Class-H Boost in Audio Amplifiers [pdf]


@londons_explore 11 days

Replying to @type0 🎙

This seems like only half way to the ideal solution...

The ideal solution would be to use a DC-DC buck boost power supply to directly supply the speaker. Get rid of the intermediate power rail and ESR losses by effectively converting the power twice.

Obviously you will need to do some work on the control algorithms, because rather than your power supply aiming for a nice stable output voltage, you're now aiming for a voltage waveform exactly matching the target signal. You also no longer care directly about ripple voltage, but do care about linearity and THD.

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@watersb 12 days

Replying to @type0 🎙

Good times in the 2000s with the Tripath amplifier chips. Vinnie Rossi took them out of mass-market Technics surround sound boxes and created some really nice amplifiers.

Then he rolled his own, using batteries to drive the amplifiers, independent of the AC mains electric supply. A 2007 deep dive at Six Moons warning very heavy audiophile reality

https://6moons.com/audioreviews/redwine8/

I have a base model Signature amplifier and I really like it. Rossi followed up with improved models that replaced the sealed lead-acid batteries with LiPo, and then ditched the batteries altogether with a super-capacitor design.

I can't find the old company, maybe it is no longer in business. But looks like Rossi has a web site still up at https://www.vinnierossi.com

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@londons_explore 11 days

Replying to @type0 🎙

It would be nice to do something about efficiency in the left half of the charts too.

I understand that my Bluetooth speaker only lasts a few hours when cranked up to full volume. But when I have it on as quiet background music I'd really like it to last a week.

Audio is perceptually logarithmic, so quiet sounds use very little energy to produce. That means that with carefully designed stuff we should be able to get really long battery lives.

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@Severian 12 days

Replying to @type0 🎙

If anyone wants to easily get into Class D amps, Parts Express has private label Dayton Audio amps [1] with a variety of features and wattage levels. They use Wondom/Sure as their supplier [2].

They are pretty feature rich: they support I2S, Bluetooth, and Sigma Studio for DSP effects (using the Analog Devices ADAU170 IC).

I myself am pricing out a kit so I can build a ammo-can speaker box. I'll probably go with Parts Express as it's a 1.5hr drive to visit the brick and mortar store, and I can get the speaker drivers as well (plus other components).

[1]: https://www.parts-express.com/electronic-parts/audio-amplifi... [2]: https://store.sure-electronics.com/

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@Tsiklon 12 days

Replying to @type0 🎙

I wonder why these haven’t become more well known among Audio folks, more power at higher efficiency is a good thing, if it comes with suitably appropriate low levels of undesirable distortion

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@skybrian 12 days

Replying to @type0 🎙

Interesting. Are there any products that use this? Development boards?

I hope to build a musical instrument someday with an integrated speaker.

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@aftbit 11 days

Replying to @type0 🎙

Class H sounds a lot like envelope tracking in RF.

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