High end Class D amps?

Your source better have low output impedance as well. The NC500 modules are fairly low impedance on the input.

Any one don’t be scared off doing this if your source is up to the task, 2k input impedance for the NC500 is not so bad, many retail class-D amps are that anyway.
Even a 50ohm source impedance is fine into that, most high gain good dacs are contenders for this hook up. And the best buffer is no buffer.
My dac is 1ohm output with 200mA short circuit current, nowhere near full volume, absolutely no problem . 

@ kh007: Oops I stand corrected. Thanks!

@grk, Tommy uses an in-house designed Class D solution instead of adding a custom buffer to off the shelf modules, and they sound terrific.

bluorion: 
You wondered about Mola Mola.  Of this I can speak from experience.  A pair came up locally for sale and I went to audition them.  I was blown away by the dynamics at the seller's home, but unsure since the system and setting were very different.  So the gentleman was kind enough to travel with me to audition the Kalugas in my system.  Again, I was blown away.
They made my Revel Salon 2's sing and explode like nothing I had heard prior.  They easily bested my current Classe Audio CA-2300, as well as the former PS Audio Stellar 300's.  I put them in and out of my system comparing the Classe.  I heard much more dynamic bass...tight and controlled..but also heard sparkle and sounds I had previously not heard.
Used, for under 7k.  I now have added the Makua Preamp with internal Tambaqui.  I believe it is the implementation of the the Class D technology, just as with any component, that makes it excellent or not.  One should not evaluate all class D amplifiers as equal.  I have my heavy amps downstairs...Audionet..and they are better.  But the size, ease, appearance  and sound of these Mola Mola components are winners!

Isn't class D just prepackaged class ab?