My experience with ICEpower
WSLam -- Mon, 10/09/2006 - 03:48
Just read the special on TAS166. First of all, I think TAS's coverage on Class D indicates that TAS is well-connected with the real-world trends. The special is well represented by manufacturers and reviewers.
Mr Harley kept on raising the following questions:
"But is Class D technology really up to the standards of high-end audio?
Can these diminutive little powerhouses deliver the musical performance of
conventional linear amplifiers? Are we trading away sound quality for the lure of efficiency, low heat dissipation, and a small form-factor?"
We are used to a world full of compromises. We all love the power of a V8 or even V12 engine (downside, gas bill, non-green etc). If you are a photographer, you know that good lenses are almost always big and clumsy to carry around, not to mention very expensive.
By putting the questions as Mr. Harley did, it is not difficult to have the assumption that because the new Class D amps are so small and efficient, therefore, we must be sacrificing something in return.
Maybe I am being a little picky, but I believe it is very important for such a 'study' to remain as neutral as possible.
To me, the question is more like this 'Is the High End industry ready for the Class D revolution?'
It must be made clear Class D is far from its infancy. Class D has been around for quite some time. With no real experiences with Class D, I have always beleived that the holy grail for amplification lies in Class A/AB designs.
First of all, not all Class A/AB designs are created equal. I am sure we all agree that you can get a good Class A/AB amp and a bad one. The same thing applies to Class D. It is important not to generalize Class D as a 'Class' of sound imo.
Now back to my own experience with ICEpower.
I bought a pair of ICEpower monoblocks because I needed something to power my surround speakers. Up till then, I have been using a pair of Mark Levinson No.33H to power my main speakers. The ICEpower was so tiny, I bought them out of the very reasons Mr. Harley questioned... small form factor, energy efficient, and hence ease of placement.
Out of curiosity, I hooked up the ICEpower to drive my main speakers. The result was astonishing. Better dynamics, more clarity and presence, and effortless control over the Revel Salon (back then). The differences were not subtle.
I am well aware that sometimes, we get confused by 'different' and 'better' sound. Different does not necessary mean better. I did not want to be overwhelmed by the difference. I let the amps play over the course of a few more weeks. I switched back to the 33H, and I *personally* really prefer the ICEpower sound over the 33H. I sold my 33H about 2 months after I bought the ICEpower.
Going back to the TAS Special report. Three manufacturers... only Mr. D’Agostino dimissed Class D, which is not difficult to understand as the other two both have Class D amps. But one of the reasons why D’Agostino dimissed Class D is because "I take exception to your comment that people “design”switching amplifiers, because most of them are based on somebody else’s chipset. What you’re really doing is designing the output filter in a way that expresses your idea of what an amplifier should sound like, because as everyone knows, there is no ideal filter for switching amps yet."
Why then does D’Agostino uses off the shelf scan speak drivers in his speakers? There is no ideal way to implement a dynamic driver either. But you do your best. I do not see where his argument is coming from.
But it's understandable, afterall, Krell uses nothing but Class A in their new lines of amps.
Class D in general may not be better then Class A/AB in general at this point, but there is no doubt that Class D will mature and evolve to a state that you have to question why waste 80% of the energy when you could be only wasting 10%? Did CD not 'win' over LP? Did MP3 not win over CD? Did SACD not fail? Is CD always worse sounding then a LP? All these questions can be applied to Class D.
Quote:I am well aware that sometimes, we get confused by 'different' and 'better' sound.
'Different' could just as easily be confused with 'worse' sound. I am not sure whether it is the AB or class D that has the 'better' treble.
It is clear that identical modules can be made to sound quite different by other implementation details although none yet to Mr. D’Agostino's liking. It is understandable in that I have not been a big fan of Krell amps so I guess we prefer different output filters.
Quote:'Different' could just as easily be confused with 'worse' sound. I am not sure whether it is the AB or class D that has the 'better' treble.
Well, I am. At least on the basis of the small sampling of Class D amps I've heard. BTW, for me it's not a question of "better" treble but of "more lifelike" or "more natural" treble—treble which has more of the air, openness, and bloom of the real thing. With the exception of Bruno's Kharma amp (and even it wasn't quite as open and airy and extended-sounding on top as my $$$$ Class AB references—or, for that matter, as the $ Class AB Parasound Halo A21 that I will be reviewing in Issue 168), the Class D amps I've heard (including the ones I heard at RMAF) sound a little like CD used to sound (and to an extent, still does) in the treble—as if there were a hard ceiling up there above which nothing resides but dead silence. Worse, you can hear this ceiling as you approach it—not just when you get to it.
That said, I think Bruno’s amp is a gem and am still rather haunted by the midrange of the (ICEpower'd) Rowland 201, which (in sharp contrast with its—to my ear—unnaturally curtailed treble) was gloriously rich, airy, bloomy, and detailed—fully competitive here with linear amps that cost a good deal more than it does. If Rowland could extend those midrange qualities into the top octaves and add a bit more dynamic life to the whole package, he’d have a killer-good amp, albeit a killer-good amp that is voiced like a Rowland.
I’ll stick by what I said at the close of the Editors’ Roundtable. No one’s dismissing Class D. It has genuine virtues that go well beyond convenience and form factor. But it does seem to me—and several of our other editors—that, like early CD, Class D amplification is still very much a work in progress and that different companies are currently on different rungs of the ladder when it comes to making progress.
Voicing remains a tremendous balancing act. Especially the top end. I can get the mids and lows of an amp right using nearly any decent pair of speakers as long as I've had time to get used to them, but with the highs this becomes difficult.
So, whatever one does, the loop is always closed through the ancillary equipment. The speakers used mostly for voicing the MP150 were the Exquisite Midi's. Other speakers were used for cross-checking but not for making actual sonic decisions. The diamond tweeters on the Exquisites are incredibly wideband and phase accurate on the top end. An amplifier voiced to sound "just right" using these speakers may well be judged somewhat restricted on a system with "normal" tweeters. The question then becomes "are we judging the amp or the speakers?". Likewise, an amp voiced on other speakers may eventually sound "just right" on those. When it is subsequently paired with the Exquisites, the setup is liable to have an excess of "air and extension" (yes, in audio you can have an excess of virtues, this is called "euphonic") that will get a lot of people hooked.
Which speaker to consider "right" and whether to consider "excessive qualities" a good thing or not becomes a philosophical question. I personally prefer to avoid euphonics at all cost (once you cater for a particular taste, someone else will hate the product) and hopefully nobody will blame me for trusting Kharma loudspeakers :)
What the reviewers perceive as a "common thread through all class D's" may well be two effects at play. Some amps do have obvious and measurable problems in the top end (frequency response, output impedance and distortion), others don't. In the latter group the top end may well be what the designer wanted.
Having passed through stages of "clearly too pronounced highs" with the MP150 I can confidently say the character of the highs in this product is the result of the voicing process.
Just for the record, Wayne Garcia, whose reaction to Class D amps (including his reaction to Bruno's MP 150) was almost identical to mine, used as his references Kharma Mini Exquisite loudspeakers, which employ the same diamond tweeter and ceramic midrange as the Midi Exquisites, the speakers that Bruno "voiced" his amp to. Wayne heard the same compression in the top treble with Class D amps that I did and Robert did and Neil did.
I myself used the MAGICO Mini as a reference, a speaker that is anything but rolled-off in the top treble. It is, in fact, the flattest-measuring, lowest-distortion direct-radiating loudspeaker I've ever come across, with substantially flat treble response on axis up to about 40kHz and a benign impedance curve.
In my class D experience (Kharma, Red Dragon, NuForce, ARC, Channel Islands, Spectron), JV is right that most of the class D amps can be found wanting in the treble when compared with very good class AB amps. And, as he has said, I would concur that the Kharma treble is the best of that class D lot, even though it has a voicing that isn't particularly synergistic with my speakers.
I have to say, though, that I find this discussion a bit one sided. I could equally suggest that all tube power amps can be found wanting in the bass, when compared with class AB amps. With tubes, though, some have learned to look past the problems to glory in the benefits.
So, while from a technological development perspective the "early days of CD" analogy may hold, I think a year or two from now we will also be aware of a "later days of tubes" analogy for class D amps. That is to say, we may come to think that class D amps, on average, demonstrate qualities in the bass and mid-range that outstrip the performance of even somewhat higher-priced class AB amps. While some may find the treble limitations of class AB unacceptable, just as some would find the bass limitations of tubes unacceptable, others will happily accept the treble issues to get at the bass and mid-range delivery of class D.
This thing about the treble is useful feedback for me. If anyone could name an amplifier (regardless of type) that they find roughly equal to the MP150 but with "better" treble response, I can include this amp as a reference in a future tuning session.
So far, however, I've not yet heard an AB amp that had better highs without sounding artificial (like the amp is trying to impress with its "HF extension"). I've always considered a truly neutral top end to be the biggest challenge with linear solid state amplifiers. The matter is complicated by the fact that anything you do up there has a huge effect on how the rest of the spectrum is perceived, which means that a particular mix of sonic characteristics may actually not be possible in reality.
Bruno, if you were addressing this note to me I would suggest that you listen to MBL's 9011 monoblocks in solid-state (along with the MBL 6010 D preamp, a great combo with the Midi Exquisite), the Audio Research Reference 610T in push-pull tubes, and the Lamm ML2 (not the 2.1) in single-ended triode. Other fine Class A/AB amps that I am familiar with include the Edge 12.1, the MBL 9008 (another great combo with the Midi Exquisite, Q.E.D., the sound of the big GTT Audio room at the Rocky Mountain Audio Fest in Denver earlier this month), the CAT JL-2 and JL-3, and the ARC Reference 210. BTW, none of these amps sounds alike; however, each does have a sweet, airy, extended, detailed, and energetic treble. None sounds "artificial"—at least to my ears. It is thus far Class D that has, to varying degrees, sounded “artificial.”
OK thanks! I'm sure I'll manage to get one or two of these amps for a try.
I had the opportunity to meet with Alon Wolf a few weeks ago.
Together with two of my friends, we had lunch together. These two friends, who after listening to my setup with ICEpower driving my pair of Magico Mini, all followed suit and respectively switched their pure Class A tube amps to ICEpower, and all subsequently bought a pair of Magico Mini.
To many of TAS editors, and to Mr. Wolf, I am sure our 'set menu' approach seems insane...pairing the Magico Mini but the very best of Class A amp seems to be the 'correct' path.
I have heard endless arguments about the inferior high freq of these Class D designs, but foruntately for me, I really cannot hear it. If anything, I find the clarity, and authroity throughout the low bass to midrange a worthy compromise for any high frequency artifact that I personally cannot hear.
Is the current Class D the holy grail? Of course not. I am well aware of the sonic characteristics and the shortcomings of the ICEpower amp and how diff companies (say Jeff Rowland vs Acoustic Reality) can sound. (I much prefer Acoustic Reality. JR is in fact my least fav ICEpower implementation). But it's all about compromises, and the ICEpower is already such a gigantic leap for a much higher price/performance ratio that I think the conventional amps designers simply cannot ignore this up and coming wave.
Bruno, I really want to listen to the MP150. Any idea when they will come to Hong Kong?
WSLam wrote: I have heard endless arguments about the inferior high freq of these Class D designs, but foruntately for me, I really cannot hear it. If anything, I find the clarity, and authroity throughout the low bass to midrange a worthy compromise for any high frequency artifact that I personally cannot hear.
Perhaps there is no artifact to hear. I can understand the quality of 'air' in a live perfomance. This quality can vary depending on how far back you sit or whether you have a balcony seat. I understand that certain recordings can capture spatial cues that can reveal the character of the venue. But if an amp exhibits 'air' as a general characteristic, can't this be simply an artifact of its design?
Bob
Bob,
Interesting, because I said the same thing previously in another thread. I dismiss the idea of 'air' even though I know what it is when reviewers use the word. But I simply do not agree that Air is a 'natural' acoustic quality. We all have the 'real world' as reference and I have never heard air, and I go to countless concerts a year. I can see a system being more extended then others, but air?! The 'air' quality found in many high end tubes amps, are to my ears, not 'true'. but that's me. Last time I brought this up, JV wrote a big paragraph on what air is.
The word has been so widely used that even though I don't agree with it, I use if sometimes just to get the message across to other audiophiles.
I agree with you Jonathan about the treble of most D-amps. Especially the Ice Powers I have heard. They have a bit of a bump in the lower treble that may overshadow the upper treble, obscuring air and subtlety.
I also think that the EMI most of these designs leak leads to a rougher sounding treble, not just in the amp, but it affects the ancillary equipment too. Designs that try to deal with the EMI sometimes affect the treble, resulting in a slightly rolled off sound.
I have heard the Karmas a couple times at shows and I thought they sounded very natural, probably the most natural of the D-amps I have heard. I suspected there was a synergy with the rest of the system, especially the cables. I know the signature of the Kharma cables (especially power) and I think it could be very complemetary to a digital amp. Ultimately though, I was still left with a feeling that a part of the music wasn't getting through.
I posted a thread about my impressions of the D-amps I have had in my reference system recently here: http://forums.avguide.com/viewtopic.php?t=645
My experience is primarily in tracking down and controlling RF noise in my own house and system, without the benefit of sophisticated test equipment. I am a retired electrical engineer without an income, so I have to use clever experiments and inference to make progress. Most of my experience predates my Gilmore Raptor monoblocks, when I had a bi-amped setup with OTL monoblocks on the midrange/treble and SS on the bass.
I've found that a little RF noise adds a sparkling and airy quality to many recordings. The detail seems to be enhanced. However, upon careful listening and comparison with other, better, quieter systems, it becomes clear that the true detail is suppressed.
In most cases, added RF noise degrades the midrange at the same time that it "enhances" the detail and air. Complex voices such as Thomas Hampson and Shirley Horn sound more harsh, mechanical, and disconnected.
There are a few recordings with real ambience and a low enough noise floor that the air (the reverberent space) around the instruments and performers can be reproduced by a quiet system. The midrange will be gorgeous when these conditions are met.
It is early days for switcing amps for high quality audio playback. I don't doubt that many interested users experience odd treble artifacts from many of the available amps. However, I don't think these are inherent in the technology. RF noise leakage is one obvious issue, but there may be others that no one yet understands.
There are many interesting threads going on here. For Bruno, I would second JV’s suggestions on other amplifiers to check out. After using the MP 150 as my main amp for several months, I switched to MBL 9007s (while keeping all else equal). Not only did the Mini Exquisite benefit from the extra power (even in my small room) but the treble extension and, IMO, naturalness improved as well.
And even though I was rough on some of the amps in the survey—and yes, the Mini Ex is a very revealing speaker—I agree with Tom (and believe this was the basic point of the survey): this is a still-young technology and it will be fascinating to see (hear) it evolve over time.
My experience has been with Bel Canto REF 100s and the Red Dragons. While I am impressed by the quick response to Bruno's question as to which amps to voice his Class D amps against, the list provided seems to come from a very different price category than most of the Class D amps you reviewed. I don't think that any of the Class Ds cost more than about $7,000 a pair, but I'm quite sure the mbls are far more expensive than that. If Class A and AB solid state and tube amps aren't always compared to mbls, than why should Class D amps be?
I don't disagree that mbls sound amazing, however, for most of us their pricing puts them into a league that we cannot afford. Any amp comes with some compromises, but as people with real jobs, these are things we have to be willing to trade off on. Please feel free to correct me if you think I am being unfair, but I can't remember most of your solid state and tube stereo amps reviews comparing the test subject to mbls. There's a good reason for this: it's not a reasonable comparison or one that adds much value for people that may desire mbls but cannot afford them. Unless the indirect point you are making about the Class D amps you reviewed is that they outclass everything tube or solid state short of the mbls you like so much.
Regards,
Greg
Greg,
Your point is well taken, at least in part.
It is true that the Class AB amps that I recommended to Bruno are considerably more expensive than most Class D amps. However, the second part of your premise—that I don't customarily make a comparison between my reference amps and less expensive Class AB amps—isn't the case. I do compare other amps (regardless of price or provenance) to my references, as well as to the real thing.
As you will see in Issue 168, I make more of an apples-to-apples comparison between a Class AB amp (the $2k Parasound Halo A 21) and the Class D amps I am familiar with. (I also compare it to my Class AB super-amps and to the real thing). You may find the results interesting.
As for the question of “air”—be it in the top treble or anywhere else (and it is everywhere else on records and in life)—I refer readers to pages 2, 3, and 4 of the “War declared over Magico Mini: what justifies 20k?” thread.
Al Sekela brought over his Gilmore Raptor amps today for a listen. We spent about three hours comparing them to my Shindo Sinhonia amps.
The Raptors did very well, and I would like to spend some more time with them. They had no obvious flaws. Great bass, clear open midrange, natural highs. They had no glare or edge or nastiness that could be caused by EMI/RFI. Though very neutral by amplifier standards, they still fall slightly on the warm side of neutral, sounding like the very best solid state to my ears.
I preferred the way the Shindo renders textures, gets the gestalt of the music better, creates a more vivid sonic picture. But the Raptor did very well up against a product three times the price.
So the Raptor is narrowing the gap in my experience between what's possible with digital amps and the best tube gear. I look forward to spending more time with the Raptors in the future - and i haven't said that about any of my recent D-amp experiences.
i believe RHs questions were along the line of 'devil's advocate' in nature, an advance faq if you will. i think he is neutral here and just trying to be fair.
"Did CD not 'win' over LP? Did MP3 not win over CD? Did SACD not fail? Is CD always worse sounding than an LP?" i am not sure what context is used here.
yes, CD won over LP, maybe mp3 is winning over cd for the i-generation, sacd didn't fail, it just hasnt prevailed, and mostly LP sounds better than CD. will class d/t take over? dont think so, it will proliferate, and seems like it already is on that trail.
my direct experience with class d is relatively positive and i am keeping an open mind for other info. i think some long term listening would clarify things for me. a friend has the CIA d200s and i may get to borrow them. so far i am impressed, i have heard them on two different speakers including the $60k von schweikerts.
i wasn't aware i was listening to class d when hearing the vonSs, but i was impressed by the fact that such speakers were so well driven by $2300 amps. the flap on AA about the the sonic impact $30 amp mad sense once i put thing together.
the fact the the class d phenom is being addressed here is significant and should be more widely publicised.
...regards...tr
I think what you forgot to count in this discussion is the price tag.
Digital are costing now around 5k, w/RMS 200/300CH, no A/B or tube can beat them in the price range. You hardly found A/B and tube in that price range with that kind of power output.
Shure there are a lot A/B and tubes will kill digital gear. But how much do they cost? 20k?
I have blindly undated by Cyrus II PSX to the integrated Bel Canto Ice Power amp. Problem with the Cyrus was HF compression. The S300i is an improvement in audio. I listen into the studio mix much more, perhaps too much more. Over dubbing and congested mixes sound like crap. On the other hand, purist mixes, quieter mixes with less over dubbing and less compression sound absolutely excellent. This is one clean amp. No extra's. Very fast, but not edgy on good mixes. One thing, because the damping factor is so high (>1K) I had to add a KRK subwoofer (set to minimum level) so I can feel the bass player during many of the songs. The amp on it's on tightened up the LF soo much that my IMF TLS 80 monitors with the low mass woofer sounder too light in the LF. The studio used speaker with more mass and thus more lingering LF on the bass players level.
This amp is a step into the future. A bit of a compatibility problem with what the studio's mix on SOME songs. Some songs and albums come through the amp just fine. eg Jack Johnson's album he did at home. The strong bass line is just fine through the Bel Canto Integrated.
Love Music
Since I have possesed and compared both of them, I guess I am pretty sure.
What is the difference? Only pricewice? 7000 USD vs price tag on UcD website?
Very weird
If you want MP150, I can sell a pair you at very good price.
Dear mr J.Valin, i live in Europe and very often i follow your reviews about various high ed gears.
I play at home with kharma crm 3.2 f speakers among a 22 watts SET Art Audio Jota monos high current [EML.520B tube] plus sub kharma 1.0,First sound preamp paramount S.E
I have in mind change the speakers to the mini Exquisite ones.My request is :whether the mini Exqisite carry a similar charge ,so i would have any problem regarding their driving and as second ,because i have no the occasion to hear them if worth the difference to pay this upgrade thinking about.I love the crm 3.2 f for their performance in small jazz or few instruments classical discs ,but in big orchestral discs the performance is of certain grade omogeneizated,without a precise separation between varous instruments.May i have a noticable improvement after such upgrade?
Best regards
comaris
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