Gallium Nitride GaN Class D Amplifiers

@izjjzi I can't speak for other class D designs. The sound varies from one class D to another more than it does with class A amps or tube amplifiers- IOW quite a lot.

But I know how our stuff sounds.

For reference I use LPs and CDs that I recorded- which helps since I know how they are supposed to sound. The bass issue you seem to describe doesn't sound challenging to me- I also play bass and keyboards (most of which are old school synthesizers) if that helps...

I believe Most Class D amps have low output impedance which can contribute to damping factor compared to higher output impedance tube amps. That can make a big difference in how bass sounds in many cases (not all) in that the driver is better controlled and distortion lower. When I first heard my first Class D amp in my system, Bel Canto ref1000ms, it sounded like the bass was gone. Shortly after when my ears adjusted I realized it was all there but more defined and articulate than ever compared to several prior SS amps. A decent quality sound meter app is all that is needed to put any bass level question to rest. Ears alone may well not cut it in this case.

@mapman +1, I also own the Bel Canto REF1000Ms and use them to power my distributed bass array for a bi-amp set up. No shortage of bass there and it's very fast and articulate.

When speaker designers of yore were making speakers with 32 and 16 ohm impedance damping wasn't quite as important. Back then tube amplifiers, zero feedback SET in particular known for high output impedance, were by far the norm. Nowadays with speakers being of lower impedance things have changed. It's been said by a few people I know who make tube amplifiers that the popularity of solid state amplifiers using feedback came about due to speaker designers making 4 ohm impedance speakers. Makes sense when you think about it as damping should be higher with that type of load. However, these same tube amplifier makers have said to me that anything over a damping factor of 20 makes very little if any difference. So the damping factor spec should be taken with a grain of salt as well.

I have no experience with AGD, Orchard or Atmos-phere but I have owned a Peachtree Audio gan. 400 for a year, my local HiFi dealer had it in stock and I was able to audition it and bought it, 400 watts into 8 or 4 ohms.  I am quite happy with it, very detailed, but not bright, neither forward or laid back, more neutral. Wanted a little more power for my Magnepans than I had with my old 150 watt Threshold amp.  There may be better gan amps for a higher price but I can’t complain, quite happy with the gan. 400. I think class D is the amp of the future and they are constantly evolving and getting better, and the days of the 150 lb space heater class A/AB amps are growing shorter.  

Aren't Orchard amps balanced input only?