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?


128x128celander

Showing 23 responses by orchardaudio

My GaN amps just got a great review in AudioXpress

Stuart Yaniger - AudioXpress

"Personally, I'm certainly leaning towards making amps such as BOSC the last ones I'll ever own."

and

"No matter what sort of music I played from acoustic jazz to Americana-folk to electronic progressive rock, whether my own minimally miked uncompressed recording or highly produced loud studio rock the amplifiers did exactly what they were supposed to, noiselessly, without stress or strain, and in a perfectly transparent way."


I am currently offering 14-day trial periods for the amps. You should order and see for yourself how good they are.
My amps have zero phase shift from DC to 30kHz, I have a graph of this on the website.
Here is a GaN monoblock for around $500:
www.orchardaudio.com/BOSC

You don't have to spend many thousands to get onto the GaN bandwagon.
The power is 150W in to both 8 ohm and 4 ohm. This is because the gain is lower for 4 ohm version of amp.
1. The external supplies are switching supplies. They can easily supply more than 250W.

2. My pecan Pi Streamer has 5Vrms output, which matches these Amps very well. Depending on your setup you might need preamp to reach full power.

3. The low input impedance helps keeps noise down. 

Higher gain is what causes Class-D Amps to exhibit the unfavorable "edgy" sound that gives Class-D Amps a bad rep. I am considering offering a custom gain option so that you can choose a gain to match your system.

High input impedance increases noise. This amp has an SNR of 121dB, this would not be possible with higher input impedance.

While TI makes GaN products non of their class-d modules use this technology yet, as far as I know.
It gets slightly warm. Efficiency is around 95% for the amp itself. GaN allows for very good efficiency, hence the product can be in a small package and not require heat sinks reducing cost.

The power supply is efficiency level VI, which means it is better than 88% efficient.
@erik_squires
See here:
https://lh3.googleusercontent.com/S858cTFxMhUrNiKmI-UvAlh0aknmlPi23dtmaykE_Ud4uNLs97fYHCj4ZnysAeP4kT...

At low frequency there is really no phase shift from the amp. All of the phase shift is coming from the built-in high pass filter of the audio analyzer.

There is no phase shift in the amp up to 30kHz.
http://audioaddictsforum.com/thread/818/orchard-audios-class-amplifiers-review?page=1&scrollTo=23071
Another great write-up:
https://www.audionervosa.com/index.php?topic=7264.0

Before I go into any detail, let me say up front that these amps are something special. Detail and clarity galore with a transparency that grabs your attention and doesn’t let go. The amps run cool to the touch and are so small that they can be easily stashed away out of site in any system. In my opinion, they punch way above their price point and easily turn a background music system into something that cannot be easily ignored... or at least, that was my experience.
and
Bottom line: I thoroughly enjoyed my time with the BOSC amps and think they form an amazing combo with the PecanPi Streamer. Their strength for me is that they were able to take what was a background music system at best to something far, far better.  I have no doubt that they will shine best when matched with a high-quality pair of speakers.  If you like your music open, honest, highly engaging with life-like detail readily conveyed, I think these are absolutely worth a listen.  

Kickstarter launching next week. Check out the project video:
https://youtu.be/qo4ssUfE4rg 

Sign up for our mailing list to learn when Kickstarter project goes live: www.orchardaudio.com/bosc
A pair of GaN monoblocks for under 1k!!!
https://orchardaudio.com/shop?olsPage=products%2Fbsc-mplfr

Also I would have to agree with the above that 1.5MHz frequency is not needed to achieve good results, and only presents another set of problems.
I will be doing a demo of my BOSC GaN monoblock amps ($1500 per pair) in Stamford, CT on February 1st. If you would be interested in attending please send me a message through https://orchardaudio.com/contact-us. Only 5 spots left.
I will be doing another demo in Boston on March 14th. See info below.

Location:
Mattapan Branch of the Boston Public Library
1350 Blue Hill Ave
Mattapan, Massachusetts 02126

Time: 2pm

The demo will consist of the following:
2 x BOSC GaN Monoblock Amplifiers ($1500 per pair)
1 x PecanPi Streamer ($500)
1 x PecaPi USB - DAC and Headphone Amp ($500)
2 x Infinity Primus P362 (Speakers)

Demo attendees will receive discounts.

For more info on our products visit:
www.orchardaudio.com

Thank you to the Boston Audio Society for help in organizing this event: https://www.bostonaudiosociety.org/

Facebook Event Link:
https://www.facebook.com/events/617821925723372/