New Generation Class D - AGD Audion Mkiii upgrade

@atmasphere 

Sorry, but what you are stating may be applicable to the rest of the GaN MOSFET but that is not correct for the device we use in the Audion GaNTube88KT and I will be more than happy to describe to you why.

Without boring anyone with complex terms, in short, the reason is simple.

Since you know very well the difference between fixed D% (i.e Buck or Boost converter) and variable D% (i.e CLASS-D) operations, symmetrical HB and asymmetrical HB configurations, and among other things how important the stray inductance of the switching pair at the switching node is (we switch our power stages at ~800KHz but we could go much higher...), you should easily derive which parameters and physical elements of a semiconductor device (the 3 terminals switch) need to be optimized to make it operate at best in each different topology with the ultimate goal to obtain not just the best efficiency....but in our case, a great sound...and these parameters are not the same. I assure you ;)

@atmasphere 

Well, what can I say, I am very very glad you keep misunderstanding the explanation and the physics of the semiconductors applied to power electronic technology and applications :)

@atmasphere 

I don't think I misunderstood your post, you replied to our true statement about the fact we use a specific GaNFet HB device that was specifically designed and optimized for CLASS-D (Audio) applications as not true. That was already borderline offensive since your comment implied I was making up something or worse I was a liar. Nevertheless, I very gently tried to explain the reasons and the basis of my statement, and still, you ignored them and made a further simplification inherently calling me a liar or incompetent, by saying that all GaNFet as long as are "good switching devices" are good for Class-D anyway. They are not, and you can repeat that all the time you want, it will not make it right. In any case, I found this type of argumentation a total waste of time, if you wish to get a more comprehensive explanation just give us a call and I will be glad to re-explain my statement again, for the last time. 

Dear Ralph,

my position is supported by the quality of the sound of what we make (and what I designed from the ground-up...literally), and also those few decades spent in a much less fun environment than Hi-end audio...meaning the semiconductor sector.

Now, and with all due respect, the simple fact your last reply cites the "input capacitance", is an obvious demonstration of the gap in the fundamental know-how of semiconductors in general, and for sure in III-V material devices that exists on this matter from your side. For your benefit, you know, there are multiple FOM (figure of merit) indicators in every device that are application-specific and need to be optimized, together with the package and internal device layout, to reach the optimum performances (you can ask your friends at GaN System), and in the semiconductor industry, there are millions of dollars spent every year to gain small % edge vs. competition every year and with a new generation of parts to improve just a few of them. So it is fruitless to take this venue and continue an argument over a true statement, or transform it into a "Power Electronic 101 for dummies" type of training. Also, on the same token, and maybe I need to ask forgiveness for this ;)...well...I need to confess... I am definitely and categorically not interested in telling the "secrets" about how to make a better GaN for audio to my good competitor!  Right ?? ;)

So really, in all honestly that was not my goal, I simply wanted to re-iterate what I have said, written, and publically declared, sorry if you keep ignoring the evidence in a sort of "don't look up" style.

The results of the AGD products are the proofs and for the rest, well let's leave it as is, and let's enjoy the music again, in whichever form is reproduced :)

 Thank you and have a nice Thanksgiving!

All the best!

@jasonbourne71 

"This Audion AGD is just a Class D circuit stuffed into a KT88 glass envelope. It has zero relation to a real vacuum tube. A clever marketing ploy! Add some LED's for that tube-like glow and the gullible are smitten and like Jay's Iyagi proclaim it the best-sounding amp ever!"

So for the sake of the argument please help me understand the deep intrinsic meaning of your comment by allowing me to rephrase it in a more comprehensive form like this:

“….a Ferrari is just an ICE engine mounted on a metal chassis with 4 wheels, zero resemblance to a real cart pulled by real horses. A clever marketing ploy! Add a unique logo, some brilliant red color, and a thundering sound and the gullible are smitten and like someone proclaims it is the best car(t) ever.”

Is that profound truth what the comment was originally intended to convey to the vast number of your "gullible" audiophiles brothers in music?

Just kidding, and ...assuming no one actually has listened to or owns one….a Ferrari I mean of course 😉