Gallium Nitride GaN Class D Amplifiers

In my recent research for a possible upgrade to my current amp (Benchmark (AHB2) I was reading about the new higher end design for Class D. I'm very interested in learning more about these new GaN(Gallium Nitride) designs. Three companies are offering some very well reviewed products and they are not going crazy with Watts per channel:

Orchard Audio offers a 250 watt Amp

AGD a 100 watt

Atmos-Phere also a 100 watt

What's interesting  is while Orchard is a new company AGD and Atmos-Phere have been around a while producing high end Tube amps. In almost every review it is noted how these newer designs sound like Class A or Tubes with all the benefits of Solid State. One reviewer couldn't go back to his tube amps after extended listening to the Orchard. No wonder AGD and Atmos-Phere are getting into this technology. It's very exciting as these amps are highly efficient turning over 90% of the power they draw into sound compared to about 78% with A/B designs and I believe even significantly lower for Class A. They run cool and usually weigh between 10-28lbs. I plan to do more investigation. Small size and light weight with decent power is very attractive. There are also mono block offerings for more power if needed. These are not cheap Class D products. They are well designed and constructed.

Orchard Audio's base model is around $2700and their Dual mono version with larger power supplies is $5500.

Both AGD and Atoms-Phere are $5000

Mono blocks for each are about twice the cost.

Has anyone had any experience, demos, etc ., with these types of GaN Class D amps?



On my GanFET Audions the bass was so impactful that I had to disconnect one of the two hot wires to the REL S812's. This was advised by REL if your system has so much bass that is cannot play louder than position 5 on the REL volume knob without creating excess bass.

No experience with Orchard or AGD, but I owned a pair of Atma-Sphere M-60s for a number of years, fully upgraded to 3.3 including V-Caps. After procuring a pair of the Atma Class Ds, the M-60s were sold and I've never looked back. The Class Ds are smoother in the top end, have better control of the bass, and are equal in the midrange, all of which is high praise as the M-60s sound great. I don't at all miss the heat output or the 24 tube anxiety of the M-60s; the Class Ds never even get warm, and I can leave them on all the time.

Speakers are Zu Druid V, which I've driven with 2 watts but sound way better with 50, regardless of room size.

@atmasphere Respect and regards to you and to Alberto.

Please, it is not bass I am referring to but low-end reverb(?). The two tracks I previously mentioned involve a synthesizer and organ, not bass guitar or other. I own a pair of REL 212SX and yes, Billy Eillish tracks and others hit my chest like a truck. What I am describing is the emotion of deep notes, resonance (reverb?) that you can feel. My Accuphase A36 and PASS LABS x260.8s knocked those tracks out of the park, but were muted... benign with GaN. If this piece can be solved by GaN amplifier manufacturers, GaN will be my last stop. That said, I will soon be auditioning a new player in the GaN space (ArgentPur) some time this month or so.

@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.