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DACless audio
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grumpydoc:
Random thought

If you have a "digital" audio source, say from Bluetooth or optical and a class D output amp, presumably one could calculate the PWM duty cycle direct from the digital signal and avoid what is essentially a digital->analog->digital->analog conversion.

Has any system ever done this?

Was it worth it?
tszaboo:
There are countless number of class D amplifiers with I2S inputs.
grumpydoc:
Thanks

Any end user products that you know of using them (specifically Bluetooth amps).
themadhippy:

--- Quote ---Has any system ever done this?
--- End quote ---
sort of, but not blue tooth though,more your pro pa rig ,analogue into the desk,spat out as aes into outboard processing then aes out the processors into the amps.as for being worth it,maybe,it certainly cut the latency down,but whether that was noticable to your average punter who knows
tom66:

--- Quote from: tszaboo on September 14, 2022, 02:38:12 pm ---There are countless number of class D amplifiers with I2S inputs.

--- End quote ---

I think many of these do internally do an analog to digital conversion - they use a ramp generator, DAC and comparator to generate PWM so technically they're analog (though would you ever be able to tell the difference?)

This is because to get e.g. 16-bit PWM at 48kHz you would need an PWM clock of ca. 3GHz - there are ways to get around this like delta-sigma or MASH PWM which essentially reduce the resolution as you get closer to the cutoff frequency, but they require fairly complex digital logic.

How many I2C class D amps are there that implement true digital modulation?
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