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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
 
+1, Ralph. I suspect the confusion stems from the digital inputs in some of these amps. Folks might forget one needs a DAC circuit to generate the audio signal prior to amplification via an analog stage.
jonnie22
10 posts
 
No DAC needed for the amps I mentioned. Digital-in, w/o converters, meaning a digitally-amplified signal.

How else do these power a signal ?

No-one here should listen Ralph Karsten. He knows tubed circuits and that’s about it...
ricevs
190 posts
 
Actually, the first "digital amp" was the TACT. They do not have an DAC in it. They convert the PCM signal directly to PWM. There is no analog signal ever inside a TACT (except that which is generated via PWM and outputted via the speaker outs). In their white paper they stated that this PCM to PWM conversion was "non linear" by nature and that is why they spent so much time to get it right (make it linear). Most of todays "digital amps" are using this technology. They do not have a DAC inside......they convert PCM directly to PWM. This is why I call them digital amps and why most do. Yes, the output stage is a class D circuit.
atmasphere's avatar
atmasphere
7,068 posts
 
No-one here should listen Ralph Karsten. He knows tubed circuits and that’s about it...
Engineering school only spent a day on tubes when I was going to school. You figure it out.
Actually, the first "digital amp" was the TACT. They do not have an DAC in it. They convert the PCM signal directly to PWM. There is no analog signal ever inside a TACT (except that which is generated via PWM and outputted via the speaker outs).
The quotation marks above are well-placed :)

If in doubt, Bruno Putzeys is one of the most-respected designers in the class D field. So who are you going to believe, him or someone marketing an amplifier?  Just read the paper at the link I posted and don't shoot the messenger.

stray_cat
32 posts
 
Just did a search for the Technics su-g30 and it appears some members here have owned and sold them. It seems that street prices may be more realistic than the $3999 msrp.

Maybe they'll run across this thread and chime in.



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