SET the best?

absolutely I need to confirm the GaN Fet AGD uses for the Audion, Vivace, and Tempo (either in the AGDGaNTubeKT88MKii or in the new GaN power module for the Tempo) were optimized specifically for Class-D application hence for Audio.

The article of Rick Backer is therefore perfectly correct.

I cannot disclose the name nor the products of the 2 very large customers these chips were originally intended for (customers of International Rectifier), but I can confirm these were 100% audio applications. The current GaN-Fets available today from many suppliers are indeed designed and specified for Adapters and Battery charger (pc/tablet/phone) applications, and they have therefore different characteristics (very different) than the one we are using. To use them in Class-D is possible of course, but several additional layers of circuit design optimization are necessary.

@agdproduction 

I wonder if his nose grew while making that statement?

Currently Audio is a minuscule portion of the GaN market, even at the voltages/currents of GaNFETs that would be used in audio.

Most of the ones in this range are used for high volume high performance POL DC-DC and sync-FETs in DC-DC and AC-DC. Total volume in audio for GaN is puny right now. It is primarily a marketing tool at this point.

Then again, there is the simple fact that a Class-D amp is effectively really quite the same as a DC-DC. What makes a GaN good for a DC-DC would make it good for audio and vice versa with rare exception, more so on the silicon side actually than GaN.

The quote above w.r.t. complexity just sounds like talking points from the GaN systems white paper on their ref design and using their parts in a Class-D amp versus their competitor. Their parts due have advantages against some other parts in Class-D, dependent on how used, but the claims made would be relevant to any half-bridge DC-DC as well, not just Class-D. I expect GaN is chasing this market as the GaN market is still immature and they need to drive sales to ensure continued investment. By far the most important market for them will be electric Vehicles and those devices are much higher voltage.

Odd no one here is bringing up speakers for SETs???

Sure this is  the amp page,, however with SET's speaker selection is super critcal  

THe magic of a SET only opens to the degree a  speaker allows that magic to be registered.

Basically we have 2 speaker designs that work with SET's, 

,,although my tech just wrote back,,,,He and others who have heard his SET with Gryfx SP 10 ,,double stacked!!! system,, sounds **wonderful*** I said,, **huh??**, well I guess this is a testimony to the oft misunderstood power to a  low powered SET amp,. SETs are able to drive even a  heavy load.

My tech wrote,,**you realize a  2A3 has 5 % 2nd harmonic distortion,,and is only 3.5 wtts..**

I knows he loves the KT120's in his beautifuol Webster Organ 90 mono blocks. ...so I looked up 2nd HD on the 120's,, ~~~15%~~ Lets see how he wiggles out that one,,

OK 5%,, that leaves me ~~95%~~~ gorgeous pure linear high fidelity magic.... 

The 3.5 watts, no problem for my music requirements. 

More is not better.

My Defy's 100 watts, is not going to deliver the magic of a  3 watt SET. 

Big PP power is losing to the new SET amps popularity. 

I can't imagine any benefits from class D for high sensitivity speaker.

I can!! Low noise so low its hard to hear even with your head in the mouth of the horn- and greater detail/better 'focus' so images in the rear of the sound stage are easier to hear- and overall every bit as smooth- in fact smoother.

When you combine smoothness and greater detail at the same time that's when you're getting somewhere.

Good point!

so  how would you describe the sound of a  845 tube?  I guess this would depend on front  tubes, driver/pre tubes.