Is it analog or is it digital?

It's unfortunate that class D amps are called class D since in audio D often stands for digital and the description of how a class D amp works(square waves) sort of sounds digital. Plus class D involves encoding albeit an analog encoding not a digital one.

It's sort of interesting why class D(actually pulse width encoding - variable width square waves of equal height) is class D. And it's stupidly simple. It's the 4th amplifier format defined. The 1st was class A(again not because it's best, just because A comes first in the alphabet). Then class B. Then class C(intermitant amplification and not high fidelity therefore). And the 4th format is class D. In all cases A, B, C, and D stand for nothing; they are just letters.

Probably doesn't make a whole hill of beans one way or the other.  Try both; if you can tell a difference, go with the one you prefer.

Subwoofers (subwoofer amps) should be plugged directly into the wall. They draw massive amounts of current. I would plug them directly into the wall. 

@dynamiclinearity 

It's unfortunate that class D amps are called class D since in audio D often stands for digital and the description of how a class D amp works(square waves) sort of sounds digital. Plus class D involves encoding albeit an analog encoding not a digital one.

On top of that, they got marketed as digital amps, and some of them take a digital input and don't require a line level d/a converter. They somehow convert PCM directly into PWM to switch the amplifier on and off, so the analog signal never emerges until the PWM signal goes through the capacitor on the amp's output. They can bypass a pre-amp too by adjusting the rail voltage on the class D amplifier to control the volume. I had a Panasonic PurePath digital receiver in the early 2000s that touted all these features. It was zero negative feedback too!

Still I agree with you, the class D topology is not working in the digital domain, most clearly when being fed an analog signal that it is converting to pulse widths that are not time bound by any clock rate. With the digital input it gets a little more fuzzy for me. In that case it seems like the pulse widths are tied to some clock rate. That seems like a disadvantage, and from the measurements I've seen, class D amps set up to take an analog line level signal perform better than the ones set up to convert the PCM signal directly to PWM.

On top of that, they got marketed as digital amps, and some of them take a digital input and don't require a line level d/a converter. They somehow convert PCM directly into PWM to switch the amplifier on and off, so the analog signal never emerges until the PWM signal goes through the capacitor on the amp's output. They can bypass a pre-amp too by adjusting the rail voltage on the class D amplifier to control the volume. I had a Panasonic PurePath digital receiver in the early 2000s that touted all these features. It was zero negative feedback too!

Still I agree with you, the class D topology is not working in the digital domain, most clearly when being fed an analog signal that it is converting to pulse widths that are not time bound by any clock rate. With the digital input it gets a little more fuzzy for me. In that case it seems like the pulse widths are tied to some clock rate. That seems like a disadvantage, and from the measurements I've seen, class D amps set up to take an analog line level signal perform better than the ones set up to convert the PCM signal directly to PWM.

Yep, so the lines on class D's "digital vs. analog-ness" get a little blurred upon closer inspection. For the purpose of THIS topic, it should be treated like a traditional class AB amp. Use a high current outlet or plug directly into the wall - do NOT plug it into a power conditioner's socket intended for low-power digital components.

Class D amplifiers have to employ HF filtering on their outputs, for a smooth response - this is at least vaguely analogous to a DAC's filtering in its conversion.