Class D and Power Cables

You might want to take a look at these:
http://www.cullencable.com

Yes Indeed! I just bought a 6 ft pr of Cullen Crossover PC's.
Never heard my tube amp sound so good. music comes from a "black" dead quite background right out of the box.
Better than my Pangea 9, Zu, Harmonic Tech 11's, Acoustic Zen Tsunami and MAC HC . Not by a little either.

It might depend on design of power supply. Some class D amps have straight linear PS while others (like mine) have switchers and some have switchers with power factor module. The most sensitive to power cable is perhaps linear power supply. Switching supply is less sensitive since it is regulated while Power Factor correcting type like Bel Canto Ref1000v2 have additional bank of capacitors minimizing short current spikes - a way that power supply normally takes energy from mains. All this is only my guess and I suspect that any amp can take advantage of better power cable. It is only to what extend.

Hifial is absolutely right - class D is analog. Outside it presents itself as as normal amplifier with about 1% of switching noise that is not audible but inside it operates on principle of Pulse Width Modulation (duty cycle of constant voltage square wave converted to average value of voltage). What is hard to understand is that duty cycle and not the voltage is analogous quantity (it is continuous without discrete steps)

Most of aftermarket cords are made the way they divert the sound and color it to make sure that consumer hears differences. They've been introduced into high definition audio as another layer of brainwash and source of ez money.

My experience with the d-Sonic amps I bought early this year is that they are the most grateful equipment I have yet encountered. Nearly everything i did to or for them paid out in improvements in sound. They improved substantially when given better cables. I started out with diamondback platinums, a decent entry level cord, but they really came into their own when I installed pS-Audio's former TOL Pc he extreme SC that retailed at about $1000/meter. These can be found here on agon used for under 400 now. They also performed nicely with an older pair of Synergistics research X2 Master couplers.

FWIW, I got the biggest improvement in the amps' sound quality by putting them up on isolation platforms. I got a huge return for around $200. Because they are so small, they only need small maple blocks ($90 at dawnsplatforms) and two sets of mapleshade isolation blocks ($50) and some used brass footers from the web ($60) made a bigger difference than going from the diamonbacks to the PS Audio power cords.