GaN FETs are for high frequency (>500 kHz) switching circuits and are not really meant to be run in saturation with a Q point. They have low parasitics, but that only applies at high frequencies, not audio. Using them is more marketing than any intentional advantage over a MOSFET. There are too many other factors involved to attribute sound quality strictly to the output devices.
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?