Flying Mole CA-S10 integrated amplifier Page 2
Substituting other components—an Onkyo DX-7555 CD player for the complex digital source of PS Audio transport and Perpetual Technologies/Modwright digital source, and various other cables I had on hand for the Nordost Valhalla speaker cable—also changed the sound, but not in ways that I could unequivocally say were improvements. The use of Aurios component supports, which provide a benefit with most electronics, made no difference that I could hear.
Eventually, the CA-S10 apparently reached some sort of break-in plateau (it's hard to be absolutely sure about this sort of thing), and the PS Audio xStream Statement interconnect brought its virtues more to the fore. "Resolution Revolution" is not merely a marketing slogan. The CA-S10's resolution of details of vocal and instrumental performances and spatial definition—as well as technical details of recording such as an editing glitch I've mentioned before, on Sylvia McNair's Sure Thing: The Jerome Kern Songbook (CD, Philips 442 129-2, track 10, 1:35)—were about as clear and detailed as I've heard with just about any combination of preamp and amp. The sound had a lively, dynamic quality that made it easy to follow rhythmic patterns such as those on Mickey Hart's Planet Drum (CD, Rykodisc 10206).
Having said that, musical is not the first word that would occur to me to describe the sound of the CA-S10. Perhaps accurate. I found much to admire in the sound, but even after the long break-in and efforts to provide a more synergistic match with associated components, it was still a bit too much on the clinical side for my taste. To use an analogy with digital photo processing, the sound of the CA-S10 was like a photo whose apparent ultrasharpness has been produced by somewhat heavy-handed application of Photoshop's Unsharp Mask sharpening tool. At first glance, the image looks very sharp, but a closer examination reveals that the edges have been emphasized, and that there are faint halos around the outlines of objects. I wouldn't take this analogy too far, but if the CA-S10 had a Sharpness control, I would have wanted to turn it down a notch or two. Judgments of sharpness of photos is very much a subjective thing, and people differ in their preferences. I would expect that people will also differ in their responses to the "sharpness" of the CA-S10's presentation.
The Flying Mole CA-S10 was the second digital amplifier I've had a chance to evaluate at some length; the first was the PS Audio GCC-100 (Stereophile, January 2006, Vol.29 No.1). As I still had the review sample of the PSA on hand while reviewing the CA-S10, a comparison seemed in order.
I found the products similar in a number of ways: they're both integrated amps (although PSA calls the GCC-100 a "variable gain power amplifier"), both are rated at 100Wpc, and both use class-D amplification. However, the GCC-100 is a fully balanced design, with a more extensive array of inputs, a left/right balance control, a remote control, and a numerical readout. It's also much bigger and heavier than the CA-S10 (26 lbs vs 9 lbs) and costs more ($2795 vs $2000).
In my review of the GCC-100, I said that the interconnect that sounded best with it was the Nordost Quattro Fil—better than PSA's own Audio xStream Statement. And as I've said above, the opposite was true for the CA-S10. I hate this sort of interaction! To keep potentially confounding factors constant, I used both the CA-S10 and the GCC-100 with the xStream Statement, which favored the CA-S10. For comparison purposes, however, I decided to use each amplifier with the AC source optimal for it: PS Audio Ultimate Outlet passive-filtered for the CA-S10, and one of the P500's regenerated-AC outlets for the GCC-100. Levels, measured with a voltmeter at the amplifiers' speaker terminals, were matched to within less than 0.2dB. I think precise level matching is critical only for rapid-switchover comparisons, but, hey, it can't hurt.
The most immediately obvious difference between the two amps was in their levels of noise: with the CA-S10, as noted above, some audible buzz/hum came through the speakers; the GCC-100, while not having absolutely the lowest noise I've had in my system, was considerable quieter. The noise in both cases was audible from my listening seat only when there was no music playing; at even a fairly low level, music masked the noise in both cases.
The amplifier sections of the CA-S10 and the GCC-100 operate in class-D and so might be expected to sound alike. There were some similarities, but they were largely eclipsed by the differences. Both can be described as high-resolution amplifiers that do not gloss over or smear sonic subtleties present in the source. The amps' top and bottom extensions were comparable, the CA-S10 sounding a bit cleaner in the midbass. However, the GCC-100 managed to avoid the clinical, ultrasharp presentation that characterized the CA-S10, and was generally easier on the ears, especially with music played at high level. Christiane Noll's orchestral accompaniments still had a bit of an edge with the GCC-100, but were less annoying than with the CA-S10. (This recording really benefits from the "sweetening" action of the combination of the CAT SL-1 Signature preamp and Audiopax Model 88 tube power amp.) Although the amount of detail presented by the CA-S10 was perhaps even more impressive than that of the GCC-100, listening to the latter was more satisfying in the long run.
The Avantgarde Uno 3.0, while highly revealing of differences in the sounds of components in the system, is not exactly your typical loudspeaker, so I thought it would be worthwhile to try the CA-S10 with a speaker that's more in the mainstream. I remembered that I had a pair of Paradigm Studio/20s in the closet, loaned to me to temporarily expand my home-theater system from 5.1 to 7.1 channels for the review of a surround processor. In his review of this speaker in the February 1998 Stereophile (Vol.21 No.2), Bob Reina had referred to it as being, "by a wide margin, the finest under-$1000/pair speaker I've ever heard." While he might not make the same statement nine years later, the Studio/20 is still a very fine speaker, and its price level represents a good match with the $2000 CA-S10.
The Paradigm Studio/20 is much less sensitive than the Avantgarde Uno 3.0, and, as expected, noise through these speakers with either amplifier was low enough to be inaudible unless I put my ear right up to the baffle. I won't recount all the ways that the Studio/20s sounded different from the Unos; suffice it to say that my conclusion about the differences between the Flying Mole CA-S10 and the PS Audio GCC-100 didn't change: the CA-S10, while impressively detailed in its presentation, was a little too clinical for my taste.
The Flying Mole CA-S10 was a difficult product to evaluate. First, its sound seemed to change during the evaluation period, making it hard to pin down its ultimate sonic character. After a good three months of use, I would assume that the sound quality had plateaued, but it's hard to be absolutely certain. The sound of the CA-S10 was also highly influenced by the choice of interconnect feeding its input, and by the nature of the AC power source, the supposedly superior balanced power resulting in a higher level of noise.
After prolonged break-in, and with AC source and associated equipment optimized as much as possible, the CA-S10 produced sound with an exemplary level of clarity, detail, dynamics, and bass extension. However, I found myself merely admiring these sonic aspects without being fully drawn into the music. While the CA-S10 delivered on Flying Mole's promise of high resolution, the sound also had a clinical, somewhat synthetic quality that tended to keep me at arm's length from the music. Of the CA-S10's class-D output stage, audiophiles who dislike digital amplifiers on principle might very well say, "No wonder—it's digital!" However, I didn't have this reaction to the PS Audio GCC-100, which is also class-D.
These responses may not be shared by everyone. If you place the highest value on an amplifier that delivers the utmost in sonic details, the Flying Mole CA-S10 may be the right one for you, especially if the rest of your system complements its sound. It just didn't float my boat.