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?


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But they would say that they make them.

In a similar vein, I have seperately talked to two Class D amp designers. Both said what is important with Class D is the design and layout of the amplifiers. The design requires a good knowledge of Class D, which a lot of other amplifier designers do not have but they are learning fast. They both agreed that one issue is not the 'magic bullet' whether it was GaN or not. So GaN may improve Class D amps but only if done well by someone who understands these circuits and not just because they have the GaN label. As always it may be best to wait and see what happens when the amps start appearing and get to hear what they can do. GaN may be a busted flush despite what the tiny THD numbers say.
I’m not sure whether the following thread was reposted here, but FWIW, a musician and professor of music presented his review of the Merrill Element 116 monoblocks vs. the Merrill Veritas monoblocks. From what I can gather, the Merrill Veritas monoblocks are Si-based Mosfets implemented in a class D design. In short, the OP preferred the SQ of the GaN-based class D design of the Element 116 monoblocks.

https://forum.audiogon.com/discussions/comparative-thoughts-merrill-audio-element-116-vs-veritas-cla...

Thanks for that link, missed it. I assume this is a discrete component amplifier as opposed to the nCore Veritas but I have not seen any internals of the 116s.
All I know about the Merrill Element 116 monoblocks is on their website. They allegedly include the GaN-based MOSFET’s in a class D design. 

Lots of class D and class A and class A/B amps are better than the old Merrill Veritas......not a current reference. Listen to the $8000 Nuprime Evolution amps......these might give the latest GaNs a run for the money for a lot less. Then there is the latest (just now being released) version of the DAC Megacherry amp ($6100)......I am sure there are others, as well. We need some GaN amps less than $15,000.........I bet within a year we will see some. By the way, DAC and Nuprime each have their own patents on class D and make there own stuff.....no stock modules from other companies. There is no reason why a GaN amp should be any more than $100 more than a mosfet based amp. So, in a few years, you will see $500 GaN amps......even kits. I think we will see a Nuprime GaN amp within a year (it is in development now).

The most exciting thing about GaNs (assuming they make Class D better) is that you will be seeing more and more integration in audio. Imagine a 2 or 3 channel GaN amp inside a speaker with digital input circuitry, electronic xovers and room eq. No more speaker cables, analog line cables, multiple power cords, racks, etc. You just have source and a couple of Ethernet cables going to your speakers with built in everything.....including GaN amps. We are talking super sound for the masses. The source box would have an A2D converter to convert your phono stage (or other analog source, if any) to digital to run to the speakers......very cool. Cannot wait.