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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?


celander
celander's avatar
celander OP
1,036 posts
 
Marantz PM-10 is a conventional integrated amp. It does not appear to include a class D amp section, let alone a GaN-based class D amp section. So this post is misplaced. This forum thread is focused on GaN-based class D amps.

The GaN-based technology are power FET transistors made of Gallium Nitride. They are used in power output implementations, not in the power supply section.

The benefit of a GaN-based FET power transistor over silicon-based MOSFET power transistors is how well the GaN-based FET transistors track the input signal on square wave measurements. One needs to see a picture of such a measurement to understand this point. The upshot of all of this is that deadtime is reduced, overall negative feedback in the amplifier circuit is dramatically reduced or altogether eliminated, among other things.
ricevs
190 posts
 

George,

If voodoo means listening to things and using the best sounding things then certainly I am a super voodoo lover.

Everything sounds different.  Most things that make a difference sonically cannot be measured.  I just did a listening test of three different female xlr input jacks (Neutik, Cardas and Furutech).  All three sounded different.  All three measure the same.  This is the same for solder, wire, capacitors, fuses, resistors, damping, shielding, power supplies, bypass caps, etc. etc.   All these things make the sound different and yet they all measure the same.  This is from my direct experience of over 40 years of listening tests.  This is why every single amp from every single manufacturer will always sound different.  Believe it or not!  It is not my belief.....it is my BE LIVE......for experience is the direct truth......you have to listen to know!

tweak1
870 posts
 
Perhaps good news for GaN prices. I stumbled across this YT video from CES regarding GaN amp from CREE of all companies. 

https://www.youtube.com/watch?v=gYHY_XKv5tY
Post removed 
georgehifi's avatar
georgehifi
4,966 posts
 
ricevs

George,

If voodoo means listening to things and using the best sounding things then certainly I am a super voodoo lover.


No, I called voodoo for saying "Measurements mean very little." they are very important if you can interpret them.
If you are good enough to interpret measurements, as designers and bench testers are and "audiophiles" that bother to learn, then one can correlate the the way a product measures to the way it behaves when listening.
EG: An efficient 98db 6-8ohm speaker. But with 3ohm impedance dip, and a -60 phase angle at 100-200hz, everywhere else it’s pretty flat at 6 to 8 ohms, that’s why the manufacturer calls them a 6ohm speaker.
Any tube amp will sound thin and lifeless because it can’t drive those speakers properly between 100-200hz. (a 3ohm load with -60 phase angle will have an EPDR that looks to the amp like it’s driving 1-2 ohms!!!) And if you don’t know what EPDR means then I suggest you look it up, there’s a few pages "technical" explanation in Stereophile.
https://www.stereophile.com/content/heavy-load-how-loudspeakers-torture-amplifiers-page-2

All you have to do is read Stereophiles reviews that the reviewer had a question mark on a part of the sound, and 9 x out of 10 JA will have a part of the bench test measurement that correlates to what the reviewer heard.

And if "audiophiles" bother to learn learn those measurements, then you won’t have thread questions like "I bought these speakers what amp will sound the best with them" and you’ll get many pages of answers that have no chance of being correct just personal favoutrites, and this thread starter gets on the amp merry go round trying to find the best amp.
But there’s one or two that will give the right answer and the reason and links to the measurements to show why it’s right, and they cross their fingers and hope that the thread starter has bothered to take it on board and at least tried to understand what he said.

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