Which Class D Amplifier? PS Audio, Ghent, Nord, Merrill or other???

Hello atmasphere,

Thanks for the update. Very interesting and surprising, too. I’m not surprised you’re building your class D modules by hand but I thought you’d decide to utilize the faster switching GaN FETs in your amp. I would think not using them would handicap your amp’s performance in relation to the competition. I assumed you’d choose the best parts for each amp function in order to optimize overall performance.
I’m just an enthusiast of good music played through high quality audio equipment but even I can hear the improvement in sound quality of the ADG Vivace mono blocks despite listening to them on a YouTube video on a laptop via headphones. I think the improvement would likely be even more obvious and impressive heard in person.
I may be attributing too much credit to the faster GaN FETS, rather than the typical silicon MOSFETs , for the improvement in sound quality I hear in the new ADG amp. I know there're many other design factors involved in determining an amp’s ultimate sound quality.
But I understand that you’re an amp designer who’s also responsible for running a successful company and there’re very important factors involved in your choices that I’m not aware of. You certainly don’t owe me an explanation, I think I’m just a bit perplexed and disappointed.

Best wishes,
Tim

^^ The reason we aren't using GaNs yet is we are in a prototype stage. We developed a means of eliminating the need for dead time circuitry in class D amps (for which we have a patent pending).

The main reason to use GaNs is to minimize dead time (dead time increases distortion). So you are seeing GaN-based class D amps right now that have no dead time circuits simply because the transistor is so fast that with conventional switching speeds no dead time circuits are needed.


We're able to switch at the same speeds with conventional devices.


What this means is that for any given semiconductor tech that comes along (GaN and whatever **will** follow) we'll always be able to switch at higher or equivalent speeds with older technology (which is less expensive, although GaNs are already pretty inexpensive, being only about $3.00 each). Of course the flip side is that we can use the latest tech and switch faster. But in a prototype that sort of thing isn't necessary.

noble/Tim, et al

UPDATE: I replaced the old (~ 10 years) mid line PS Audio XLR with WireWorld newest Series 8 Silver XLR ($425) WOW. after a couple hours I was hearing a grungy distortion, so I  decided to replace the  PC I was using with my WW Eclipse Series 7 PC (the one that I replaced prior to inserting the PS XLR) OMG. This is the most natural my system has sounded in many years.  Oh, and subs are turned off but the Emerald Physics KCIIs have really good bass to ~ 40, which is ample for most music. Where I was using the F4 digital filter on my Audio Alchemy Dac/Pre I am now on F1, which is the least filtered

Paraphrasing your reply, Class D is ruthless on ancillary kit and cables. They should be upgraded before bashing class D

atmasphere:


"^ The reason we aren't using GaNs yet is we are in a prototype stage. We developed a means of eliminating the need for dead time circuitry in class D amps (for which we have a patent pending).

The main reason to use GaNs is to minimize dead time (dead time increases distortion). So you are seeing GaN-based class D amps right now that have no dead time circuits simply because the transistor is so fast that with conventional switching speeds no dead time circuits are needed. 
We're able to switch at the same speeds with conventional devices."

Hello Ralph,

     I would like to retract my complete previous post addressed to you.  I had a hunch you had your reasons for not using the new GaN FETs, but I had no idea those reasons were so completely awesome and with a patent pending, to boot. This is really big news that sounds like a major breakthrough in your class D amp efforts to me.  

Breaking News: Atmasphere Ralph just killed dead time.  Congratulations!  
    Please accept my apologies for ever having doubted your judgement.  The legend of your amp engineering and design prowess just continues to grow. Best wishes on your patent application.  Yahtzee!

Thanks,
 Tim 

tweak1:

"Paraphrasing your reply, Class D is ruthless on ancillary kit and cables. They should be upgraded before bashing class D."

Hello tweak1,

Great to hear that you’re benefiting from the detail and clarity of class D technology to significantly upgrade your system’s ancillary power cords and cables. I had similar improvements in my system by installing custom made XLR cables between preamp and class D mono blocks and power cords on my monos (all ordered from James Romeyn Music LLC). I also installed dedicated AC lines for the monos that made obvious improvements.
Similar ancillary kit and cable changes, as well as the quality level of source recordings, were never this clearly noticed through the decent quality class AB amps I previously used.

Enjoy,
Tim