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?


Previewcelander
I heard an older Spectral amp with megaHz bandwidth, fast slew rates of 700 or so.  So what?  It sounded rolled off in HF (merely 5-12 kHz that I can hear) and mellower compared to my little Bryston 2.5B SST2.  Even the Spectral seller agreed with my findings in his room.  At least he was honest, despite most sellers who say their product is best no matter what the listening finds.  They typically lie about what they really hear.

Specs are almost meaningless.  George's words are useless without his own listening findings, which are rarely or never reported.
All I can say is this thread went into the crapper. Thank you George, I'm out. Notifications now turned of.
Hey, some one please tell me, if you look at all the Class D threads over the past 2 years, which single poster has most bashed it?? I mean, like hundreds and hundreds of anti-Class D posts?

It’s like a religious thing with this guy.

You would think that if Class D was universally that bad that audiophiles would all shriek at the sound. They'd fall over with foam coming out of their mouths from the signals reaching their ears. 

Instead, most audiophiles can't tell if it's Class D or not. 
I am sure we can pull it back ron1264, but it will likely take judicious use of the report button. Unfortunately, some people have very dogmatic views that are not based on a deep knowledge of a topic, but a very thin knowledge. Though ricevs and I posted rather definitive information, there was no change in behavior. This is what happens when you approach a data set with limited knowledge and are unable to understand there are different approaches and different trade-offs that will yield different results. One could use a higher filter frequency and allow more switching residue in order to minimize bandwidth. One could use feed-forward techniques to reduce the impact of dead-time. One could use an all-pass analog filter to compensate for the phase-shift to achieve closer to constant group-delay. These are the things real working designers know (at least some of them), not the knowledge of arm-chair designers.   On top of that, is the knowledge of what is "audible" and what is not. A knowledge that some also lack. Put together it is dangerous combination.