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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?


128x128Ag insider logo xs@2xcelander
celander's avatar
Ag insider logo xs@2x
celander OP
1,036 posts
 
George, I saw this website earlier during an internet search. I thought it was interesting though not relevant for HEA applications. Most, if not all, of the applications were in the Microwave or RF amplifier frequency areas. But yes, AD is in the game.
georgehifi's avatar
georgehifi
4,966 posts
 
though not relevant for HEA applications.


Think your wrong there, we need to look beyond the forest to see the trees.
The whole advancement of "affordable" hi-end GaN based technology Class-D amps making an impact, hinges on who will start making the "component level" GaN semiconductors.
So yes Analog devices and Texas Instruments making them is relevant to this thread, as if no BIG semiconductor manufacturers pick it up, you won’t have affordable GaN based Class-D amp to purchase, they’ll all be $10K+

Cheers George
celander's avatar
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celander OP
1,036 posts
 
As more class D audio amp manufacturers enter this market space, competition will drive down prices. The GaN-FET is a minor cost component to the overall design. End of chain designers acquire license to use the GaN-FET when they buy the GaN-FET’s from a GaN-FET manufacturer, to the extent that patents covering the GaN-FET are still in force. Those who buy their GaN-FET devices as part of somebody else’s GaN-FET modules are going to pay the middleman/patent holders of that module tech. So pick your poison: buy from an independent designer who develops his/her own circuits or go buy from an outfit who builds amps with another’s module-assemblies.
agdproduction
6 posts
 
Sorry George,
you are the not really correct on this matter.
RF GaN business is totally different and requires different type of transistor design than the one needed in power management. Among other things, RF GaN transistors are Depletion mode type, so they are normally "ON", not a good start for any power converter circuit. So they are not applicable/usable in Audio (and in all other power) applications.

georgehifi's avatar
georgehifi
4,966 posts
 
As more class D audio amp manufacturers enter this market space, competition will drive down prices.
The only way this can happen, is if the major semi conductor manufacturers get the licence to make the GaN devices, this is what happened to Mosfets years ago, at first they were very expensive then prices came down when more were being made by different manufacturers.

RF GaN business is totally different and requires different type of transistor design than the one needed in power management.
I know this, but it’s the GaN technology that’s being used, and they will hopefully start manufacturing audio output GaN transistor as well.

And your in the box seat for now AG with your $15k amp, as a low volume manufacturer is in the prime seat at the moment if GaN transistor don’t go big time quantity manufacturing. Because if companies like Sangway can get hold of them for a dollar each bought in the in the thousands, then they make complete $100 modules with it, well you know what happens!

Cheers George
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