I know a lot of companies say they have a 'digital amp' but if they also say its class D then the DAC is always at the input to the class D circuitry.
That's what I always thought. Thanks for confirming, Ralph.
Digital input amp
I see a few coming on market. Previous threads were quite old.
They take a USB or other input. No DAC on the front end. Just the DSP engine to do volume, eq, etc, then whatever conversion to PCM to feed the class D output. So the only "DAC" is the output stage. This makes sense as it further reduces the functions in the chain. I have not seen objective testing or any reliable subjective testing. The ones I have seen are Infineon processer based. No idea if the output filtering or feedback implementation is up to the Purify quality. I guess the next innovation is the GaNFET output. One has a DAC to feed a sub out. Easy as any old $5 DAC will wo there.
I was browsing and came across the Sajab A30a. ( quite inexpensive) Peachtree has the old Gan-1 but coax PCM only. That would be fine if it managed buffering and clocks internally. Unfortunately my all-in-one only has USB out.
I suspect there is a lot to be learned here but it makes sense to me for the future.