Direct Digital Amplifiers

Seems as though only the TacT/Lyngdorf direct digital amps are capable of high current output. Are there any others?

The tact s2150 amplifier is all digital with built in dac. Just plug in your transport via aes into the amp and you're ready to go.

Bombaywalla, Class D amp doesn't convert anything to digital. It converts analog voltage to analog duty cycle of square wave and back to analog voltage thru filtering....

you are right, Kijanki. I was trying to be simplistic in the interest of explaining the concept.
OTOH, Kijanki, a 2-level signal which is going from logic0 to logic1 could be considered a (very simple) digital (or binary) signal. Such a signal is both analog & digital. It has infinite resolution like an analog signal & at the same time it is discrete since it transitions from logic0<-->logic1 with no other state in between.
So, I do not think that I confused anything here. Both your comments & mine are correct.
But, yes, it's not a tradition digital signal like the one that is quantized with finite # of bits.

Kijanki, I know of a least one amplifier brand (tube) that only has one stage of gain. That's pretty simple- far more simple than any class D amp.

Atmasphere, that's true but output power is very limited while in class D it depends only on power supply and size of output Mosfets.

Bombaywalla, Adjusted analog quantity is duty cycle. For instance, when you adjust oscillator's frequency by turning knob it doesn't matter if output signal is square, triangle or sinewave - your adjustment is still analog. The fact that voltage jumps between two level's doesn't make it digital if adjusted quantity is duty cycle. Also, amplifier doesn't make any use of these levels other than converting to output voltage by taking average value (filtering).
Distorted electric guitar (square wave) dosn't make it digital. FM radio is not digital in spite of voltage moving between two levels.