Hi mitch2,
You have an excellent system.. I've never listened to either the class D Acoustic Imaging Atsah or the class A Clayton M300 monos but I've read many very positive reviews on both.
Just the thought of comparing the diminutive Atsah class D monos at 1/4 the weight and size of the pure class A Clayton monos seems like a big mismatch to me reminiscent of David vs Goliath. I suspect you were not very surprised that, in this modern rematch, the favored Goliath clearly beat the underdog David,
I appreciated your articulate description of your impressions of the sound portrayed by the Atsah:
"In my case, I described what I heard as a soundstaging type of issue where the music sounded as if it were being played by individual players recorded separately in a sound booth, instead of a band playing on a stage together. The ambient cues were not present in relation to the musicians to the extent I was familiar with from my other amplifiers."
Besides giving me a clear understanding of why you were disappointed by the Atsah's presentation, the thought struck me that this poor performance may be a result of a very revealing amp combined with poorly engineered and/or poorly recorded source material.
In an effort to be totally honest about this, I need to assure you I'm making my comments less as a definitive explanation and more a joint exploration of the forces at work in your system.
I don't have the experience with NC1200 based class D amps that you have but I've used 3 mid-level class D amps in my system for the last 3 years. I'm familiar with how very neutral and revealing these amps can be of upstream components, system cabling and especially the quality of your source material; a well engineered recording will sound exceptionally good but a poorly engineered recording will reveal its flaws just as faithfully. I've occasionally experienced a similar affect as you describe on obviously poor recordings played through my D-Sonic M-600 monos that utilize the newer Anaview/Abletec AMS-1000-2600 power modules.
My suggestion is actually more of a question to you than a statement:
Could it be that the reason the musical material that you played through your class A Cayton M300 amps sounded so good, while the same recording played through your very accurate and revealing class D Atsah sounded so poor, was due to the musical material not being as well engineered as you originally thought? In other words, Do you think your class A Clayton M300 amps are less revealing and more forgiving of bad recordings than your Atsah?
Your other impression on the Atsah, that "the ambient cues were not present in relation to the musicians to the extent I was familiar with from my other amplifiers." I find this perplexing since, typically, good class D amps are very accurate, neutral and detailed, not known to add or omit anything to the audio signal.
I find it very interesting and informative that you own and have compared 2 such diametrically opposite amps: The high powered, large and heavy Clayton M300 monos which are pure class A, highly praised for their excellent sound performance that are the least efficient of amp types and the high powered, small and light Acoustic Imagery Atsah monos which are class D, praised by many for their very good sound performance that are the most efficient of amp types.
I recently read a quote from Bruno Putzeys, the inventor of th Hypex NCore class D technology, that may be of interest to you and other readers of this thread:
" I can emulate the sound of pretty much any amp out there if I wanted. But so far I'm resisting. If ever I give in, it'll be obvious from the measurements and I hope someone calls me out on it. Anyhow that's why I decided I actually wanted the NC400 to have this unvarnished dead-pan delivery."
Putzeys interestingly stated the main benefit of using class D is efficiency.
He also stated he tweaked the Hypex NCore 1200 module in his Mola Mola Kartuga monos to differentiate his amps from the numerous OEM class D monos on the market that utilize his standard NCore module.
Perhaps someday soon he'll tweak some modules to emulate the sound of the Clayton M300 pure class A monos in either his own or one of his OEM customers' amp.
Sorry this post was so long,
Tim
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