GaN-based Class D power amps


The use of GaN-based power transistor tech is now emerging for Class D audio power amplifiers. Seems appropriate to devote a forum thread to this topic. At least 3 companies have commercial class D amps in their books:

Merrill Audio, with their model Element 118 ($36k per monoblock, 400 W into 8 ohms, 800W into 4 ohms), Element 116 ($22k per monoblock, 300 W into 8 ohms, 600W into 4 ohms) and Element 114 (coming soon). 
https://merrillaudio.net

Review of Element 118 at this link:
http://www.enjoythemusic.com/superioraudio/equipment/1018/Merrill_Audio_Element_118_Monoblock_Amplif...

ADG Productions, with their Vivace Class D amp ($15k per monoblock pair, 100W into 4 ohms). (The designer emailed me indicating he has another product in the pipeline.)
http://agdproduction.com
Review of the Vivace Class D moniblocks at this link (warning: link might not work (1/11/2019)):
https://positive-feedback.com/reviews/hardware-reviews/agd-production-vivace-gantube-monoblock-ampli...

Technics SE-R1 Class D stereo amp ($17k per stereo amp, 150WPC into 8 ohms, 300WPC into 4 ohms) 
https://www.technics.com/us/products/r1/se-r1.html
Preliminary review of the Technics SE-R1 at this link:
https://www.stereophile.com/content/technics-se-r1-digital-amplifier
Technics also has a lower priced GaN-based class D integrated amp in their catalog:
https://www.technics.com/us/products/grand-class/stereo-integrated-amplifier-su-g700.html

Anyone listened to or own any of these amps?


celander
ricevs, you might be over-reading the review a bit. I interpret the Technics design architecture (from the Technics website) to reflect a configuration comprising a DAC, an analog Preamp and Class D Amp. The digital inputs are fed to the DAC for conversion to analog signals. The preamp section processes and amplifies all analog signals from both the DAC and analog inputs before sending them to the GaN-FET driver stage of the amp section.
It is not clear whether the cheaper Technics is a digital amp or a class D amp. I will use these terms because it is very clear. A digital amp takes the analog signal and coverts it to PCM though an A2D converter and then converts it to PWM. A class D amp takes an analog signal and converts it directly to PWM. The only way I found out the larger Technics amp was a digital amp was to read the very clear review I linked to.
A class D amp is class D whether or not its driven by a DAC. Pulse Width Modulation is an analog process that some Class D amps use. But that is only one encoding scheme and class D amps have at least three; the other two are Pulse Code Modulation and self-oscillating.

There is no such thing as a ’digital amp’. All ’digital amps’ are actually class D amps with a digital front end.
I am hoping that some of these manufacturers show up for APOXNA in Chicago this year. Sounds like HEA is done and out at CES.
What it says is that the "output stage" is class D......it does not say how it is driven.
Strewth!! it’s Class-D using GaN technology and Jeno (Jitter Elimination and Noise-shaping Optimization) just like it’s $20k Technics big brother the SE-R1!! doesn’t mater if it takes a digital input or analog, it’s still a Class-D amp.
https://www.technics.com/us/products/grand-class-g30/network-audio-amplifier-su-g30.html
Good luck with your venture??.



I’ve noticed a pattern, that the only ones whinging, or finding invisible problems to turn people off with the GaN technology. Are the ones with "some sort" of vested interest or ownership in the older Class-D topology, that are built around readily available "off the shelf" Class-D modules, be they Hypex, IcePower, Pascal, Tripath, or Sanway ect.
I think we would see a different story with them I think, if a complete GaN based module was available to all, for around the same price range as the older technology above.

Cheers George