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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
 
Enjoy the board then. I’ve got higher standards. 
celander's avatar
Ag insider logo xs@2x
celander OP
1,036 posts
 
Does anyone know what the input impedance of the AGD Vivace monoblock amp is?
guidocorona
4,114 posts
 

Hello Celander, the Vivace's home page does not seem to list input impedance.... Perhaps Alberto Guerra can chime in on the subject.


Saluti, Guido


  

georgehifi's avatar
georgehifi
4,966 posts
 
Enjoy the board then. I’ve got higher standards.

Please list all the item no.’s in the BOM list I posted that you or someone else would improve on, and with what and why?
https://www.scribd.com/document/398286093/EPC9106BOM-1


Cheers George
vt4c
27 posts
 
GaN can generally handle higher voltage and has smaller die area thus lower capacitance and easier to switch. A silicon carbide substrate will better heat transfer as that material is better than silver in conducting heat.
The "sound" is in the digitizer and stability of the power supply. Peak loading of the power supply will cause the same issues as any power supply.
There is no real advantage in class D unless you (really) need a lot of power, like driving 50 speakers to earpiercing levels or drive an electrodynamic shaker for environmental stresstesting where 30 KW may come in handy.
Of course as people have reported here they can be made to sound as good as other types, with more effort. So really why use class D? There is no real advantage, just more complications. 
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