Atma-Sphere Class D… Amazing

@srama

yes, I did. I got the ultimate upgrade. fed from a wavedream net and dac stack. hooked up to the Atma-Sphere monos using TWL Spirit ii xlr. I really like this combination. I'm using it with headphones though (abyss TC Phi). the overall gain is a bit high but there are gain controls on the cary, and I reduce the output volume at the dac too.

lovely sound imo. great low end, lush mids, and sweet highs. I have no intention of changing out the cary pre. although somewhat annoyed at the black gloss finish as it does collect microscratches even when using a microfiber cloth to wipe it down. also, the blue light led on the power section failed, but my local dealer got it fixed really fast. 

@docroasty

Thank you, that's good to know. Weird, about the power meter led - it seems to be quite common, although I read somewhere that Carey did fix the issue back in 2018 or thereabouts.

Does the quote above suggest Alberto (AGD) is misleading in his saying his GANFET is made for audio?

No- not in my opinion. IMO it suggests he had a batch made that have low output capacitance. Low output capacitance reduces ringing in the output section (which is also caused by circuit board trace inductances and power supply issues- they can be in parallel with the output capacitance of the device which results in ringing and noise) as it switches and thus helps the devices to run cooler. The ringing can be controlled by a snubber filter but the output devices will still run hotter. So a low output capacitance is desirable.

In practice we found no need for a snubber circuit as there was no detectable ringing. IMO GaNFETs allow for lower noise designs. I think this is very important as switching noise and parasitics can mess with digital equipment even it the amp meets EU emissions directives. So you want to be many dB below the maximum allowed by most government entities. We found that many tube amplifiers radiate more noise than our class D.

Thanks for responding @atmasphere. In a interview, Alberto says he was involved in the initial development of GANfet. I believe he said he bought the stock and patent for the Mosfets he uses. 

A brief history of gallium nitride (GaN) semiconductors