Atma-Sphere Class D… Amazing

@noske 


 

That is quite a slab of tests. I think that someone who owns one will drop-ship one over to Amir at ASR. Probably a couple weeks turnaround.

It's quite typical these days. I can assure you most bona fide manufacturers do much more than what I have listed.

My understanding is someone has already sent one for testing, or is in the process. We should know fairly soon how it "measures up".

Yes, I am aware of Atmasphere's recent entry into the class d market. I have already previously remarked that it is an impressive feat for someone who has previously been an exclusive designer of tube amps to make the leap to class d, which I know is a whole different ballgame. Bruno Putzeys once described class d amps as wanting to do everything but make music, or something to that effect, meaning, one must overcome their inherent nature and climb many mountains to tame them. No doubt it is a tribute to Ralph to produce something which on subjective grounds seems to have attracted a following on his first go around.

@ghasley I simply found important to clarify to @noske, the user that called in AGD (and Atmasphere) implying a possible lack of experience (compared to Purifi) on the matter of technology, specifically on Class D and Silicon. I brought to his attention what the fact are. Is it something that is not allowed in this forum?

@aw-agd 




 

With all due respect, Silicon Mosfet cannot compete in performance nor on future FOM (Figure of Merit) improvement with GaN based semiconductors, it is not a matter of opinion, it is physics.

Really? Seems to me as a practical matter, silicon mosfet based class d amps by Hypex and Purifi clearly illustrate performance that not only competes with current GaN amps but in nearly all cases I am familiar with beats them handily in most objective parameters. One can argue that GaN devices offer inherent advantages over silicon mosfets, but unless the implementation exploits those advantages, it is all just a marketing scam. To date I have seen many GaN amp's brought to market, few that actualize these theoretical advantages.

@kuribo 

An informative post with alot going on here. First, I admire that you are tackling a pretty complex DIY active three way speaker system. I also admire that you've been a class d amplifier user for over two decades. Especially so given the evolution of class d amplification during that span.

Now that you have communicated you are in the market for six channels of amplification AND that you can afford to purchase anything you want....I'm still not sure that would change Ralph's mind on supplying you the data you require. It might keep him up at night that you might need troubleshooting assistance with your electronic crossover and getting things to sound right.

@kuribo Yes, really. As I said it is physics, not a matter of opinion. However you are absolutely right about the implementation issue. GaN Mosfets are much more challenging to use in order to take full advantage of the intrinsic superior performances. Without a deep knowledge of the device physics and experience with the device package mechanical issues, stray inductance, gate drives and overall layout, any improper implementation can demise terribly the electrical and sonic performances. But that it is also true in general since the same argument applies to the implementation of circuits with Tubes, Bipolar devices, Silicon MOSFET, in ClassA, B, C,D, E, F, G, H amplifiers (all topologies of amplifiers).

Hope my answer is helping in clarifying a bit more the subject.