Core Audio Technology's "Kratos" - a digital amp

Category: Digital

About two months ago I did a review of Core Audio Technology's entry-level power supply for the Mac Mini which can now be found on the forum on Core Audio's website. Since then, I've added their Kratos digital amplifier to my system and feel like I'm ready to give some thoughts.

I said it the first time around and I'll say it again -- I think this company's gear is a game changer. I went to the New York audio show this weekend and came away feeling extremely good about my Core Audio Tech stuff. My most recent setup -- which is about as bare-bones a system as Core Audio Tech offers, and which is already somewhat out of date by the standards of this extremely fast-moving company -- sounded quite excellent versus most of what I heard there -- and probably better than just about any digital configuration I remember hearing there regardless of price. Indeed, I found myself mostly comparing the sound of my system to the high-end vinyl setups. To be fair, there were a few that probably left my setup in the dust in most respects - the Walker Audio room comes to mind - but those setups also tended to have price tags well over $100k.

Core Audio Tech's owner Ryan Mintz tells me I'll experience a pretty dramatic improvement with my next upgrade. That slightly boggles me, but at this point I'm also inclined to believe it. I won't delve into technical details here, as those are pretty well laid out on the site, and Ryan is quite responsive to queries via email. Essentially, the company takes a radical approach to shortening and simplifying the signal path and feeding it with super-high-quality power supplies. Among other things, that means getting rid of as many separate components and cables as possible. It's a philosophy that made sense to me from the get-go, and left me wondering why nobody else seems to be doing it. After listening to this gear, I'm still wondering this. So rather than obsessing about interconnects, power cables, speaker cables, tubes and tweaks, I'm obsessing about upgrading to the next-level power supply, upgrading the external clock and its power supply, upgrading the music server, simplifying the signal path by converting my system to an all-in-one unit, etc. The thing is, unlike with a lot of past tweaks and upgrades, I am pretty confident that each upgrade I make now is going to make a real difference.

As I hinted above, this is digital audio that sounds very un-digital. To me, that's about as great a compliment as I could give it. I've always been a vinyl guy at heart, and when I talk about my vinyl ideal, I'm not talking about warm and fuzzy, I'm talking about the real stuff. I'm talking about vinyl that delivers a huge, lush, energized soundstage, seeming to load the room with torrents of musical information with each passing instant - a presentation that's bold and effortless, stimulating yet relaxing, capable of sounding not merely "life-like," but even "better-than-life-like." Truly, in a good vinyl setup I've always felt that when the needle is descending toward the vinyl groove, my black-and-white world is about to go Technicolor.

So does this entry-level setup - the Kratos digital amp fed by my Mac Mini with the Core Audio Tech power supply - get me there? Well, to an impressive degree - to a greater degree, for sure, than any other digital configuration I've heard that doesn't involve a DAC with a price tag well into the five digits. The key thing for me is that it delivers an analog sound without resorting to "smoothing over the edges," the way most digital equipment that claims to sound like "high-end vinyl" does.

What do you get instead of smoothed-over edges? I think of it as a lush meadow of sound, bristling, chirping and grunting with a plethora of pleasing detail. Yes, it untangles Wagner and Mahler wonderfully. The whole presentation is nicely balanced from top to bottom. There's deep, tight, textured bass. Trebles are extended and refined, yet proportionate and not in your face. On good recordings they can veer towards a kind of silky beauty. A recording of a cheering crowd in a live arena, for example, recently struck me as sounding a bit like waves crashing on the beach. That's the kind of thing I pay for. Hi-hats and cymbals sound like actual brass discs that are vibrating after being struck by wooden sticks, as opposed to the tizzy white-noise-inflected crashes that are typical of lesser digital. Horns bite, but cause pleasure rather than pain when they do. The harmonic richness, the timbral accuracy, and the dynamic finesse, micro and macro, are all wonderful. Charles Mingus' upright bass is an exquisitely crafted box of aged spruce and maple that's getting manhandled, flailing violently to punch its way out of the vise-grip it's in. Sarah Vaughn's voice is uncannily convincing: deft and precise, sensible and sad, spookily hanging between the speakers. Like a small mirror might fog up if you held it there.

So we're obviously a little inspired here. Still, it's not necessarily all things to everybody. The soundstage, while impressively three-dimensional and large, mostly hangs in a space that's even with the speakers. Folks that want a bowling alley to open up behind the wall and spill into the neighbor's yard may need to do some work. And while the Kratos seems to be almost supremely fast and transparent, that might come at the expense of a certain palpability and fleshiness to the presentation that I get with my beloved Sam Kim Heathit EL84 integrated in full triode mode. This comparison also holds somewhat true versus a Red Wine Audio Signature 30.2 LFP-V integrated amplifier I recently took in on trade (a special amp in its own right for sure). It should be said, however, that my speakers, the Tonian TL-D1s, also share that tendency, and I am guessing that many other speakers might deliver significantly more flesh when paired with the Kratos. Lastly, there still are some digital artifacts evident in the presentation on some recordings - the roughed-up Steinway in Glenn Gould's 1982 issue of Bach's Goldberg Variations is still a bit of a challenge - there's a wee bit of midrange glare and fatigue there. A piano, of course, has an enormously complex sound that is probably the most difficult thing for digital to get right in my experience - especially when it's being played hard and closely miked. But I must emphasize that it's an impressively small amount of this trouble on a fairly small minority of recordings. Most Bill Evans recordings, for example, fare far better.

Meanwhile, well-recorded classical and jazz, as well as rock like Fleetwood Mac, Steely Dan, the Eagles, etc. - even if it's redbook and recorded in 1959 - really does come very close to sounding like it's coming from a kick-ass vinyl rig. Thrilling. And again, this is despite - or rather, because of -- the fact that the Core Audio system appears to be doing nothing to cover up or paper over the distortion with something slow, smooth, opaque or otherwise euphonic -- what Ryan likes to call "pleasing distortion" that's getting in the way of the real music. It's also despite the fact that my Tonian speakers are not known to be the most forgiving.

The issues notwithstanding, I'm mostly impressed that the performance is already as good as it is despite being an entry-level setup. For the first time, I feel that I'm not fundamentally disappointed with my digital. I'm getting the musical flow, the "time, tune and tone," the "fun factor" that Ryan likes to go on about if you end up getting into a conversation with him (always interesting and educational, in my experience). Come to think of it, it really is kind of like stepping into a Technicolor Oz, in that I no longer feel susceptible to being bored and "watching the music go by," which was the key complaint I've had for years with most digital.

It should be said that the break-in period for Core Audio Technology gear is, in my experience, lengthy. But it's also not without its rewards. Like the power supply for the Mac Mini, the Kratos amp started off sounding pretty good, but took a week before it started to really impress, and frankly, more than a month before it started to blow my mind. Up until a few days ago, when I traded away my Mini and PS to upgrade to a new Core Audio configuration, the system seemed to be having fresh spurts of improvement each week. Frankly, it strikes me that this puts Ryan in a slightly awkward situation, given that his free trial period is only 30 days. But the stuff does sound plenty good at that point.

So bottom line, unless I hit the lottery and am in a position, for example, to splurge on a Walker Audio Proscenium Black Diamond turntable, I'm pretty sure I'm going to remain relatively undistracted by all the other stuff that's out there. But even if I do hit the lottery, I can't imagine also not simply splurging on upgrades to what I've got now. Above all, I'd encourage folks who are afraid of a digital amp that sounds "digital" to have no fear. I wouldn't say the amp sounds like tubes exactly, but I wouldn't say it sounds unlike tubes either (like flea-watt SETs with more watts, maybe). The thing keeps getting better with break-in, and the more it breaks in, the more it sounds -- a bit of a revelation for me, mind you -- exactly like I want it to sound.
Do you stil like the sound of your Kratos Amp? I have the mac mini mod by core audio and think its comparable to the mojo power supply/mini combo.

Im a little less impressed with the Kratos and Harmony systems core audio offers. They are clean sounding but have a thin sound maybe its the speaker matching that was the problem. They are comparable to the nuforce or hypex class D amps i think, very similar sound. The build quality of his products is definitely sub-par. For how expensive it is the quality is horrible, loose connections everywhere. Would like to see your thoughts now on the Kratos after living with it for a while. I would never buy his stuff anymore after hearing horror stories from other audiophiles.
I would sure like to hear other opinions on this gear????
I can't comment on the digital amp but I have been a customer of Core Audio Technologies for several years (I have the Mac Mini external power supply) and Ryan is always eager to please. He is very creative and has the technical abilities to make these ideas come to life. My whole system is based around my digital playback so I am very grateful that I found out about Ryan and plan on sticking with him and his latest designs as things progress. I would recommend his products to my boss.
Does anyone know of comparisons with NAD M2 in terms of sound quality?? M2 is 4 y.o. and has come down to apx $4500. I've heard M2, and it's luscious and built well with lots of features, but I could use the $$savings elsewhere in system, if Ryan's technology has equal or greater sound quality.