Lyngdorf does exactly that (feed PCM into amp). Check out their
SDA-2400. Analog is converted to digital on that amp or you can feed it digital directly but there's no DAC in the normal sense.
My understanding is that amps deal with electric signals (voltages and current), not bits. You can't feed bits into an amp, unless the amp incorporates a D/A IC (or similar device) which transforms the bits into something the amp understands and can handle. In other words, amps don't understand bits.
Now if we consider Class-D amps, if you feed them bits then you would need a switch (or similar device) to perform the D/A conversion, not unlike what D/S DACs do. If that's all that it has, then one way to think of such a device is a basic 1-bit DAC, which can output sufficient signal oomph to feed directly to transducers. But that's all it is: a 1-bit DAC. For instance native DSD processing can be implemented that way. For PCM input, a 1-bit switch will require all high-bit PCM content to be converted into 1-bit changes, which again is not unlike what D/S converters do. (Although it must be noted that modern D/S ICs usually use 3-5 1-bit switches working in tandem, and that pure 1-bit switches are more rare nowadays.)
Thus "digital amplifier" is just fancy marketing for a basic 1-bit DAC (or if you will a "switching amplifier") --- either way it's a variation on the 'integrated DAC/amp' theme. You'll find some people, including Schiit engineers, have strong opinions on 1-bit devices and their role in high-end audio.
On the subject of "digital amps",
@Jason Stoddard has been quite
emphatic:
"Never, ever gonna happen."
And Class-D amps sit
poorly with Schiit's philosophical approach to engineering:
In the philosophical domain, Class D amps are mathematical transformations of analog to pulse modulation, which is not really congruent with our approach of "preserve the original bits/signal." It's the same as our objection to DSD.
In other words, I wouldn't hold my breath on Schiit going down this route anytime soon...
I did a blind comparison. I have to say Devialet more than held its own - I'd recommend a listen if you folks at Schiit haven't heard them - it's pretty innovative and good sounding stuff.
