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
Here is what David Robinson of Positive Feedback replied to an inquiry about how the Mola Mola Tambaqui Dac (that he had just described the sound of) sounded versus the Playback Designs MPD-8 DAC (which, I believe he has possession of):

"We do not do shoot-outs or product vs. product comparisons at PF, as a general rule.

Prices vary; tastes vary; capabilities vary; systems vary; synergies vary; price points vary.

Therefore, we usually focus on characterizing the product in hand."

I am sorry, but this is not good.  How are we going to know which one to buy?  Do we have to buy a whole bunch of things and A/B in our homes?  I believe in positive feedback.....I also believe in truth..........please tell us your truth....what do you think?  I know, the bottom line....Yenom!

Car magazines, Camera Magazines, etc. have no problem telling you exactly what they think of various products.  Is audio a secret society?  What a silly game.  Oh well.  Have a great week.  As I said....eventually it all comes out in the wash.


Positive Feedback is .... IMHO a rag. I don't really pull much of any value out of their reviews. Recently read a review of an "exotic" cable and there was virtually no verification of claims made by the company  (some of the claims literally were Wikipedia extracts and not even applicable to their specific material usage). It was error after error. Is it par for the course? Maybe. That was just my latest exposure, and can't say I have ever come away with a "Positive" impression of an unbiased analytical review.
Well folks, like I mentioned earlier in this thread, I have heard the Technics SE-R1 vs the AGD Vivace. I'm not one to put up some long winded post, that is why I don't post that offen, I would rather just listen to music then fight like children on here. But here are my brief impressions. Both amps sound great, but different. The AGD overall was the winner, better midrange bloom, smoother highs (very slight but noticable) The Technics had an overall "thinner" sound, It remind me of the Lygndorf 3400 I had, but not to that extent. The Technics was being used with its matching SU-R1 Preamp (if you wan to call it that). Dynamics were great on both amps, the AGD edged out the Technics, but the AGD did run out of steam before the SE-R1 if pushed harder. The AGD had a musically denser presentation. Overall the winner to my ears as well as my friends ears was the AGD. 
Well folks, like I mentioned earlier in this thread, I have heard the Technics SE-R1 vs the AGD Vivace
And like I also said back then, please show to links to the proof where you heard these side by side.

The AGD overall was the winner, better midrange bloom
Fake gutted 6550 tube, with GaN SS circuit stuffed into it. https://www.stereophile.com/images/020720-Tube-600.jpg

https://encrypted-tbn0.gstatic.com/images?q=tbn%3AANd9GcS044YwyoCTJPP91rVr3bPQJbxPfIm4fS3fIg&usq...

You’d be better off buying a GaN Evaluation Board from the GaN inventors EPC. (sadly out of stock now)
https://www.digikey.com/product-detail/en/epc/EPC9106/917-1090-ND/5036827

https://www.digikey.com/products/en/development-boards-kits-programmers/evaluation-boards-audio-amplifiers/789?k=GaN




The very first GaN versus GaN sonic test and it does not go the way George likes it.  His reaction is priceless.  George, please describe your sonic tests of your 1.5 meg GaN amps versus other 500K GaN or none GaN amps?