Which Class D Amplifier? PS Audio, Ghent, Nord, Merrill or other???

I am loving this thread! I did months of exhaustive product research on class D amps last year, going back 4-5 years, all in search of musically effective (as well as powerful) class D amp options for my extremely crowded desktop (literally nowhere to put a >150WPC class A/B amp).

I ended up buying a used Wyred4Sound ST-500, and I must say, this thing has been one positive surprise after another. I never had top-of-the-line SS amps (my big amps were tube; I used SS only for subs or casual systems). The ST-500 is far and away better than any SS amp I own/have owned. Perfect for this desktop, and w/more than enough power for the ATC SCM12 Pro passive monitors, which really can take a lot of power.

I'm filing away the Nord amp comments. That amp really interests me, and if I can find one used for a reasonable price, I'll get it. 

The quest for better sound goes on, even though what I have is really quite good...

Slimpikins5 stated:
"Fast forward: I was further piqued now about Class D and wanted to get into something much more advanced, so I picked up a pair of Anthem Statement M1 Class D mono blocks which run around $7K for the pair. These babies put out 2000 watts per channel at 4 ohms (my speakers) and all I can say is; holy moly I was blown away at how much better they play than the Class A/AB amp I have been using!   Far more dynamic range, better soundstage and imaging, no high frequency harshness at all, just super clean floor shaking output."


     I find your description of the improvements you hear from your Anthem Statement M1 class D amps,  "far more dynamic range, better soundstage and imaging, no high frequency harshness at all, just super clean floor shaking output",  to be very similar to the improvements I've experienced upgrading to the D-Sonic M3-600-M class D monoblocks.   
     I just wanted to add a few additional comments about my experiences for the benefit of readers who haven't yet listened to a good class D amp in their systems.  I suspect my comments will ring true to all owners of good class D amps, also.
      I was initially struck by how quiet these amps are.  Music just seems to emerge from a dead silent background with absolutely no background noise that is verified by their excellent Signal to Noise Ratio measurements.  I believe this, along with extremely low distortion measurement levels, combines to result in an exceptionally detailed and transparent overall presentation that also allows for a sound stage illusion that is remarkably 3 dimensional and stable ('in the room' sensation on well recorded tracks). 
     Another quality that is quite obvious upon first listen is the overall neutral presentation.  I was actually a bit concerned about this quality since I thought I preferred a more flavored sound tilted to the warm side of the spectrum.  I had used a VTL 2.5 tube preamp (with NOS Mullard tubes swapped in) expressly for this purpose in my system for years.  After careful comparison with and without the tubes in my newly class D amplified system, however, I discovered my music sounded just as sweet and without any hint of harshness without the tubes. 
     I thought my tubed VTL would always be in my system and I had even  just bought an expensive quartet of replacement NOS Mullard tubes for it.  But I felt I had to trust my ears, so I sold my beloved VTL to a buddy and have no regrets.
     I think the above descriptions by slimpikins5 and myself are a good summary of what to expect from a good quality class D amp.  Just remember that there arevariances in the performance quality of class D amps just like all other amp types so try to audition any candidates in your system prior to deciding. 
     But I'd still prefer to know your needs, system and budget before offering specific amp suggestions. 

Tim
     

Must agree with "frame1" 

"Try ClassD Audio. Excellent product and value. Tom, the owner is great to work with.
http://classdaudio.com/"

I've got the ClassDAudio SDS470C, which sounds virtually as good as all the other amps I have, or have heard (e.g. Atma-Sphere M60's, Parasound JC'1's, etc.).  Though my Linear Magnetic 219ia may have a bit more "ethereal" tube sound, which presents a very "real, live" sound.  

And... his amps are an unequaled value.  

As Noble 100 stated in his experience with a quality Class D amp, I fully concur; its the lack of noise, extremely low distortion and amazing detail that struck me right off.  

And since I am such a 'green eco' type, I don't feel guilty with running these mono's for hours on end as they are so efficient.

Here is an interesting point of note:  my Anthem M1's do not come with a schematic which I wanted to read with an engineer friend of mine.  I called Anthem and asked if I could get a copy and they told me no.  They will not supply any schematics to the public, only to authorized service technicians.  I asked why they have this policy and I was told that they invested millions of dollars and years of time developing the M1 design and they consider it proprietary in all respects.  I can understand this philosophy and I don't blame them.

I was interested in how they handled the mitigation of high frequency harshness which inexpensive Class D designs are known to suffer.  The M1 is so smooth that it's uncanny.  And if anyone is interesting in looking online at some of the YouTube videos on it, you'll be quite impressed with the copper heat pipes which are liquid filled (some type of alcohol I am told) which draw the heat through convection currents away from the finals to the heat sinks on the side of the amp.  These amps feel like Capt. Kirk's USS Enterprise to me :)

I have a system with a pair of Sonus Faber Amati Futura and a full loom of Nordost Valhalla.
My first amp was Audio Research DSI200. A Class D amp with a somewhat warm and rich sound. Nice if you are looking for a slightly "tubey" signature.  
I then switched to Jeff Rowland Continuum S2. This is has a cooler presentation with slightly better bass control. It was good but I felt like it lacked "soul". 
So I left the Class-D world and found the magic in an A/B called Gryphon Diablo 300. IMO this amp is way more organic and soulful. The bass control is miles better than the Jeff Rowland despite it had 2x800 W. For some reason it was not the perfect match for my speakers who venture under 3 Ohm in the bass region. I always thought I had a "bass problem" in my listening room. It turned out the solution was getting a better amp.