Atma-Sphere Class D… Amazing

Pstores, I am waiting on my amps to ship. Then I will see how they compare to the M-60's , which I love. Also using the MP3 and a Shindo preamp I alternate, cause I love them both. Thanks for the write-up!

Acman3 your really going to like them…. 

Does anybody really think Ralph would’ve potentially undermined his own core business and introduced a Class D amp if he really didn’t believe in the technology and its potential? I consider this to be one of the very, very few components I’d be willing to buy blind and expect to be nothing but thrilled, and I so respect Ralph for embracing new and promising technology due to his objective assessments of its capabilities rather than relying solely on his past considerable success. Most impressive on so many levels and falls solidly in my “holy crap I never saw that coming” category.

I have Atma-Sphere Class D and suspect it outperforms every other brand in its price category.

I can’t recall if Ralph mentioned anything about break in time, but he did say they have virtually no warm-up time to achieve best performance. I never noticed anything to contradict Ralph’s statement. Idle current is so low that it invites leaving them on 24/7 yet if the amps happen to be cold, they need little to no warm-up to sing.

A friend of mine is interested in an A-S class D integrated. He mentioned having read that Ralph’s Class D "sound like a tube amp" in only the best way. I have heard various models of Ralph’s OTL and a lot of great brands of tube amps.

I agree with Ralph and others who say his Class D sounds like the M-60 OTL above the bass range, which by any metric is a long-time tube amp gem (having won more awards than maybe any other current production amp.) It seems important to add this caveat: the ideal OTL load is between about 12 and 16-ohm with benign phase angle, which is rare, plus higher than average sensitivity. Class D has no such current limitations and can drive loads below 4-ohm which is verboten for OTL and a ratio of transformer-coupled tube amps.

OTL have a unique signature in the bass range, not necessarily worse or better than SS, just different, hence the qualification "above the bass." In the range of bass instrument fundamental tones, Ralph’s Class D sounds like a good typical class D amp: quick, neutral, superb and powerful. Of course, bass harmonics extend well into the midrange and treble where the Class D is very transparent in this category.

AFAIK for all Ralph’s prior amps, Ralph included a U-shaped copper shorting pin. Using the RCA input required users to short XLR pins 1 and 3 (1 is neutral/shield, 2 is positive signal, 3 is inverted signal; 3 shorts to ground to shunt the entire inverted section of the balanced input to minimize potential noise.) The RCA input of current production A-S Class D requires NO XLR shorting pin, hence none is included. Ralph said shorting XLR pins 1 and 3 has no effect on noise while using the RCA input.

Class D is clean. Seems like they just added some distortion and charge $5.4K for it. DIY NC400 Monoblocks will outperform these as a fraction of the cost.