Another marketing gimmick?

That’s just an aesthetic take on a what reviewers say is a great sounding amp. It’s a Gallium nitride power FET device that only the maker has access to, since he designed it. All other GaN devices are for radar and if used for audio, are modified or backward engineered. It replaces silicon devices as it’s way faster.

No, he designed the circuit, not the GaN FET used in it. He had some involvement when he was in the semiconductor industry, but it was not designed for his amplifier. It appears to be obsolete as well as he bough the remaining inventory and is changing to a different FET for newer designs. Your comment about all GaN are designed for radar is simply not true. Switching devices in power conversion (which is what a Class-D amplifier is), is a primary market for GaN and there are numerous devices designed specifically for this from a growing number of vendors. They are not even very expensive any more with low quantity orders under $2.00, and volume much less.


The switching FET is just one aspect of Class-D as well.

While Class-D is efficient, there is still heat generated. Putting it inside glass is going to maximize the temperature swing from turn-on till it reaches operating temperature. If you like to keep your amplifiers off, till used, it may not be ideal for consistent performance.

Marketing? .... Definitely, but the upgrade path is interesting and this method ensures the unit does not have to be opened. I wonder if those contacts are audiophile grade? $20-100 speaker binding post, $0.25 cent tube socket contact ..hmmmm.

If evacuated of air it would get hotter. There are some gases that would improve thermal transfer to the glass, but thermal conductivity of gases is inversely proportional to molecular weight, and they escape easiest .... i.e. helium and hydrogen. Neon may be a reasonable compromise. There are some more esoteric ones out there. Most of the heat transfer is because of the gas moving due to diffusion and chimney effects from the hot electronics.  With the electronics in a sealed enclosure like this, most of the heat transfer will be radiative.


Nitrogen is not a noble gas. It also does not make your tires run any cooler. That is an old myth. It may from a practical standpoint in that it escapes slightly slower than plain air so better chance your tire is properly inflated, but that's it.

The GaN device he is using is obsolete. That is why he had to buy up all the inventory. That is why he needs to switch to a new one for the next gen devices. Designed for class-D audio is specious. Designed for a particular implementation of Class D audio would be more accurate. That does not mean that new generic devices are not more appropriate to Class D either. When he says power supplies does he mean high voltage supplies as mentioned elsewhere in the article (or website) or the new low voltage GaN FETs that are low cost and very high performance? ( And could be why the old part is now obsolete, too expensive and not good enough). It’s sort of like power supply electrolytic audio capacitors. They used to be "superior" but circuit dependent a new low ESR, high temp, high life capacitor will be superior.


His circuit may be awesome and I am happy to see he is not running with blinders to the highest switching frequency at the detriment of other properties (as certain people promote), but also note he is switching much lower than say Cherry who does it with silicon transistors and has well respected sound (at less money).


And no, using "radar" makes you the pill, not me. If you were up on low voltage GaN for power supplies you would have said that but sure, claim someone else is the problem.