Attack of the Clone Amplifiers

[PaulF]

4) I do not know where you find any dismissal of FCC compliance. Maybe you were thinking of FTC for the power rating. I clearly stated we were seeking FCC certification.

That's good to hear but normally FCC certification is gained prior to product release. To be fair though I don't see the compliance on any other ICE-based amp integrators' products either.

I look forward to seeing a review of your product.

 

[PaulF]

And this is a big problem. So many so called "Audiophiles" are simply hung up on the bad class D amps of the old days, and that these amps are only good for subs, that they are not really willing or able to give the new amps a fair shake.

Even this review is not immune to this problem. Gene put a lot of focus into playing music with a strong bass line rather than focusing on the entire spectrum of music. The rest of the music came across to me as more of an after thought.

Until these ingrained biases are put aside, I don't think the class D amps will get a fair shake.

It's not just an ingrained bias, there is some science behind this. Much of the performance problems of a class D amp comes from the dead time between switching the output transistors on from the two supply rails. This dead time is usually finite, so as the frequency increases, the relative phase error and THD does too. The feedback mechanism is far more able to cope with lower frequencies. In a sub the frequencies handled are two orders of magnitude less than a full range amp.

 

[VladP]

Interesting thing is that despite these clear technical compromises with class D design (or at least with ICEPower design), there are literally dozens of reviews (both here and in Europe) of various ICEPower-based amps and ALL of them are either very good or simply stellar.
Here are just a few reviews:
http://www.10audio.com/wyred4sound_st1000.htm
http://www.6moons.com/audioreviews/wyred/monos.html
http://www.ultimateavmag.com/amplifiers/808wyred/
http://www.positive-feedback.com/Issue39/wyred4sound.htm
http://www.6moons.com/industryfeatures/icepower/icepower.html
http://www.acoustic-reality.com/articles/eng_highfidelityreview.pdf
http://www.acoustic-reality.com/articles/eng_asp.pdf
http://www.audiophilia.com/wp/?p=1223
http://www.hometheaterhifi.com/power-amplifiers/594-bel-canto-s500-power-amplifier.html
http://www.hometheaterhifi.com/power-amplifiers/11-a-secrets-power-amplifier-review.html
http://www.hometheaterhifi.com/power-amplifiers/438-a-secrets-power-amplifier-review.html
http://www.6moons.com/audioreviews/eone2/1000.html
http://www.soundstage.com/revequip/belcanto_ref1000.htm
http://www.positive-feedback.com/Issue38/belcanto_ref1000.htm
http://www.avrev.com/home-theater-power-amplifiers/mono-amplifiers/bel-canto-e.one-ref1000-digital-mono-power-amplifier.html
http://www.stereotimes.com/amp041509.shtml
http://www.ultraaudio.com/equipment/bel_canto_e_one_ref1000.htm

There are more...

I am yet to read a bad review of these ICE amps. In these reviews these amps are compared to many linear amps and almost always favorably. If even cheaper linear amps are better based on some technical specs, why are all these reviews so highly positive? Even by random chance you would expect a share of bad reviews. Does it mean that these technical shortcomings are not really crucial for our sound perception? Or are all these reviewers simply wrong and they mistake different sound for better sound?

 

[cfrizz]

I don't doubt at one time there was a problem. However, I also think that it might be possible that these companies found work arounds for these problems. If that is the case, are any of these problems something that we can actually hear? If we can't hear it, than who cares what some spec/graph says.

If other problems can be solved overtime (remember the problems with the first DVD players) there is no reason to believe that the problems that existed with these amps couldn't be solved as well.

It's not just an ingrained bias, there is some science behind this. Much of the performance problems of a class D amp comes from the dead time between switching the output transistors on from the two supply rails. This dead time is usually finite, so as the frequency increases, the relative phase error and THD does too. The feedback mechanism is far more able to cope with lower frequencies. In a sub the frequencies handled are two orders of magnitude less than a full range amp.

 

[Dan Banquer]

Interesting thing is that despite these clear technical compromises with class D design (or at least with ICEPower design), there are literally dozens of reviews (both here and in Europe) of various ICEPower-based amps and ALL of them are either very good or simply stellar.
Here are just a few reviews:
http://www.10audio.com/wyred4sound_st1000.htm
http://www.6moons.com/audioreviews/wyred/monos.html
http://www.ultimateavmag.com/amplifiers/808wyred/
http://www.positive-feedback.com/Issue39/wyred4sound.htm
http://www.6moons.com/industryfeatures/icepower/icepower.html
http://www.acoustic-reality.com/articles/eng_highfidelityreview.pdf
http://www.acoustic-reality.com/articles/eng_asp.pdf
http://www.audiophilia.com/wp/?p=1223
http://www.hometheaterhifi.com/power-amplifiers/594-bel-canto-s500-power-amplifier.html
http://www.hometheaterhifi.com/power-amplifiers/11-a-secrets-power-amplifier-review.html
http://www.hometheaterhifi.com/power-amplifiers/438-a-secrets-power-amplifier-review.html
http://www.6moons.com/audioreviews/eone2/1000.html
http://www.soundstage.com/revequip/belcanto_ref1000.htm
http://www.positive-feedback.com/Issue38/belcanto_ref1000.htm
http://www.avrev.com/home-theater-power-amplifiers/mono-amplifiers/bel-canto-e.one-ref1000-digital-mono-power-amplifier.html
http://www.stereotimes.com/amp041509.shtml
http://www.ultraaudio.com/equipment/bel_canto_e_one_ref1000.htm

There are more...

I am yet to read a bad review of these ICE amps. In these reviews these amps are compared to many linear amps and almost always favorably. If even cheaper linear amps are better based on some technical specs, why are all these reviews so highly positive? Even by random chance you would expect a share of bad reviews. Does it mean that these technical shortcomings are not really crucial for our sound perception? Or are all these reviewers simply wrong and they mistake different sound for better sound?

Considering that most of the reviews you have linked are from publications that reviewed flea watt SET's and Non Oversampling DAC's favorably, why should anyone take their reviews seriously? Do you think that might tell you something about how most of this industry works?

The great thing about Audioholics is that they will tell you much more than most of these publications, and keep informative articles in the archives for your education. The choice and preference is always yours, and always will be, but Audioholics takes their responsibilty to inform the consumer seriously.

Note: Non Oversampling DAC's have no digital filter to get rid of the inherent aliasing issues. Without the digital filter you will have aliasing issues which will cause gross distortion on most program material.

d.b.

 

[rmk]

Considering that most of the reviews you have linked are from publications that reviewed flea watt SET's and Non Oversampling DAC's favorably, why should anyone take their reviews seriously? Do you think that might tell you something about how most of this industry works?
The great thing about Audioholics is that they will tell you much more than most of these publications, and keep informative articles in the archives for your education. The choice and preference is always yours, and always will be, but Audioholics takes their responsibilty to inform the consumer seriously.
Note: Non Oversampling DAC's have no digital filter to get rid of the inherent aliasing issues. Without the digital filter you will have aliasing issues which will cause gross distortion on most program material.

d.b.

And here I was thinking your posting here was just an effort to promote your competing products by slighting the competition when actually, all you really want to do is educate and enlighten. The beacon of truth shines on …

 

[VladP]

Considering that most of the reviews you have linked are from publications that reviewed flea watt SET's and Non Oversampling DAC's favorably, why should anyone take their reviews seriously? Do you think that might tell you something about how most of this industry works?
The great thing about Audioholics is that they will tell you much more than most of these publications, and keep informative articles in the archives for your education. The choice and preference is always yours, and always will be, but Audioholics takes their responsibilty to inform the consumer seriously.
Note: Non Oversampling DAC's have no digital filter to get rid of the inherent aliasing issues. Without the digital filter you will have aliasing issues which will cause gross distortion on most program material.

d.b.

I am not saying that Audioholics reviews should not be taken seriously, but they are mostly focused on the technical side of things which is their expertise. They did correctly pointed out a few technical problems with these amps. But when it comes to listening, audioholics don't really have an upper hand IMO. Listening is usually more subjective, unless proper tests are done (I have not seen audioholics conducting these tests) and people either like what they hear or they don't. Many people who are in this hobby are into live music as well and my point is that if these ICE amps really sound poor, that WILL be heard and reported. The publications I referenced all said good things about these amps. Unless they ALL have an agenda and they all are not honest, these people really liked what they heard - thus these amps cannot be that bad and most likely the technical shortcomings are not audible. Nobody would argue that it is better to fix them and I am sure future generations of these amps will get better and better. But most people who said that even cheaper linear amps sound better than ICE amps did not seem to directly compare any of these ICE amps with linear amps - did you? All I am saying that if you sample many subjective reviews by people who listen to music all the time, you would expect to find some good and some bad reviews. The reviews of ICE amps are all uniformly good which likely means that the sound they produce is good as well.

There is no question that audioholics are doing a good job by alerting the public of important issue. The question is whether these issues are crucial for sound reproduction and perception.

 

[Dan Banquer]

And here I was thinking your posting here was just an effort to promote your competing products by slighting the competition, when actually all you really want to do is educate and enlighten. The beacon of truth shines on …

Well I guess the word has spread rather slowly in some quarters; I stopped manufacturing 3 1/2 years ago.

http://www.redesignsaudio.com/service.html

d.b.

 

[rmk]

Well I guess the word has spread rather slowly in some quarters; I stopped manufacturing 3 1/2 years ago.

http://www.redesignsaudio.com/service.html

d.b.

OK, I'm a moron. I must have had another senior moment and I most humbly apologize for confusing you with another Dan.

 

[Chu Gai]

<snip>
I think you dismiss the FCC compliance too easily. It is a well known fact that a module that passes in open space may not when placed in a perforated metal box. This problem can be greatly exacerbated when using multiple modules. Who do customers turn to if their FM receivers, cordless phones or RF remotes start having problems? If you were importing these amps as a finished product rather than the individual ICE modules, Customs would require that you comply with FCC part 15 and could back it up with a certification from an independent lab.

Some may recall when NuForce first came out with their amps that people began reporting problems with their radio reception among other things. I recall reading about this at the Asylum. At that time NuForce was selling a product to the general public that had never been tested accoring to FCC Part 15. They quickly moved to both rectify the problem (AFAIK) and then submit their amps for the requisite testing. It is fairly clear to me they dodged a bullet there as the FCC seems quite willing to go after people with great success who sell things that haven't been tested which appears to be the case here. When I've voiced similar concerns to say smallish outfits who sell home brewed external DAC's I get replies similar to this one...

... Our quantities are so low that FCC or UL certification simply does not make sense, and in any case the frequencies and power low that it really isn't a practical issue. We have not gone with certifications as those savings are passed directly to our customers.

This is why I like good old moonshine...those savings are passed directly to me. Well, and maybe some methanol too

 

[Chu Gai]

Interesting thing is that despite these clear technical compromises with class D design (or at least with ICEPower design), there are literally dozens of reviews (both here and in Europe) of various ICEPower-based amps and ALL of them are either very good or simply stellar.
Here are just a few reviews:
http://www.10audio.com/wyred4sound_st1000.htm
http://www.6moons.com/audioreviews/wyred/monos.html
http://www.ultimateavmag.com/amplifiers/808wyred/
http://www.positive-feedback.com/Issue39/wyred4sound.htm
http://www.6moons.com/industryfeatures/icepower/icepower.html
http://www.acoustic-reality.com/articles/eng_highfidelityreview.pdf
http://www.acoustic-reality.com/articles/eng_asp.pdf
http://www.audiophilia.com/wp/?p=1223
http://www.hometheaterhifi.com/power-amplifiers/594-bel-canto-s500-power-amplifier.html
http://www.hometheaterhifi.com/power-amplifiers/11-a-secrets-power-amplifier-review.html
http://www.hometheaterhifi.com/power-amplifiers/438-a-secrets-power-amplifier-review.html
http://www.6moons.com/audioreviews/eone2/1000.html
http://www.soundstage.com/revequip/belcanto_ref1000.htm
http://www.positive-feedback.com/Issue38/belcanto_ref1000.htm
http://www.avrev.com/home-theater-power-amplifiers/mono-amplifiers/bel-canto-e.one-ref1000-digital-mono-power-amplifier.html
http://www.stereotimes.com/amp041509.shtml
http://www.ultraaudio.com/equipment/bel_canto_e_one_ref1000.htm

There are more...

I am yet to read a bad review of these ICE amps. In these reviews these amps are compared to many linear amps and almost always favorably. If even cheaper linear amps are better based on some technical specs, why are all these reviews so highly positive? Even by random chance you would expect a share of bad reviews. Does it mean that these technical shortcomings are not really crucial for our sound perception? Or are all these reviewers simply wrong and they mistake different sound for better sound?

You know Vlad, it's pretty hard to find a bad review of any audio product, legitimate or outright snake oil, these days.

 

[PaulF]

Vlad, there have been some positive reviews of class D amps for sure, but be careful what you read, listen to the gear and form your own opinions. Purely subjective reviews do not have the same value as those that can back up the listening portion with measurements -- AH, Stereophile, Secrets etc. Positive Feedback and 6moons are well known for unabashedly praising esoteric products with no measurements to back them up.

Take a look at the review from 6moons of the Genesis (of the speaker fame) Reference amplifier, an amp that is built from fairly low cost DIY modules available from Hypex. This makes products from D-Sonic and W4S look like relative bargains. Genesis claims modifications that greatly improve sonic performance, given the premium price I would like to see the proof.

Now the Hypex modules perform well as reviewed by Hardware Analysis. To put this performance into context however, you would have to ask how a pair of $20K linear amps perform relative the the Hypex based Genesis?

There is ample data that shows that Class D amps do not reach the sonic performance of a traditional linear amp, including B&O's own spec sheets. The Absolute Sound did broad review of many class D amps in issue 166, November 2006, as did Suono (Italian Hifi mag) across two issues in June (N.393) and July/August 2006 N.394/395). These are the most complete reviews I have seen. Both came away with Class D being OK but not quite up to linear amp standards. I still have a class D amp on a short list for my new HT room, however I know that I am trading advantages in size, weight, heat and efficiency for a little sonic performance.

 

[PaulF]

Some may recall when NuForce first came out with their amps that people began reporting problems with their radio reception among other things. I recall reading about this at the Asylum. At that time NuForce was selling a product to the general public that had never been tested accoring to FCC Part 15. They quickly moved to both rectify the problem (AFAIK) and then submit their amps for the requisite testing. It is fairly clear to me they dodged a bullet there as the FCC seems quite willing to go after people with great success who sell things that haven't been tested which appears to be the case here.

That's why NuForce is now off my list, the RFI issue and it's other foibles relating to usability, buzzing noises, unstable if disconnected etc. Then their THD spec claims 0.03% 1 kHz, 10W but when you look at their own charts you can see that at 100W the distortion never drops below about 0.28%. It's another case of cherry picking a spec. that is not representative of the amplifier performance as a whole.

 

[VladP]

Vlad, there have been some positive reviews of class D amps for sure, but be careful what you read, listen to the gear and form your own opinions. Purely subjective reviews do not have the same value as those that can back up the listening portion with measurements -- AH, Stereophile, Secrets etc. Positive Feedback and 6moons are well known for unabashedly praising esoteric products with no measurements to back them up.

Take a look at the review from 6moons of the Genesis (of the speaker fame) Reference amplifier, an amp that is built from fairly low cost DIY modules available from Hypex. This makes products from D-Sonic and W4S look like relative bargains. Genesis claims modifications that greatly improve sonic performance, given the premium price I would like to see the proof.

Now the Hypex modules perform well as reviewed by Hardware Analysis. To put this performance into context however, you would have to ask how a pair of $20K linear amps perform relative the the Hypex based Genesis?

There is ample data that shows that Class D amps do not reach the sonic performance of a traditional linear amp, including B&O's own spec sheets. The Absolute Sound did broad review of many class D amps in issue 166, November 2006, as did Suono (Italian Hifi mag) across two issues in June (N.393) and July/August 2006 N.394/395). These are the most complete reviews I have seen. Both came away with Class D being OK but not quite up to linear amp standards. I still have a class D amp on a short list for my new HT room, however I know that I am trading advantages in size, weight, heat and efficiency for a little sonic performance.

I am being careful about what I read and I also know that you cannot always make a conclusion about sonic performance based only on spec sheets. There are always tradeoffs with amp designs and the question of what is audible is of paramount importance. You can make numerous technical improvements and they may be of absolutely no use to us if our hearing doesn't allow us to hear these improvements. When you are talking about standards - you are talking about technical standards only - these are well documented. The sonic ones, on the other hand, are not documented and sonic differences are quite difficult to document properly anyway. I actually have W4S amps in my system and I only care about music, not HT. To me these amps sound quite good, especially on good recordings and I have hundreds of SACDs and DVD-Audio.

 

[VladP]

You know Vlad, it's pretty hard to find a bad review of any audio product, legitimate or outright snake oil, these days.

I am not sure it is entirely true. There is for example a fairly bad review of the Nuforce reference 9 amp (http://www.10audio.com/nuforce_ref_9v2se.htm)

I have also seen some other bad reviews of other amps, so bad reviews do exist. I do agree there are some good reviews of snake oil as well (sadly).

 

[Chu Gai]

Maybe if it was heavier?

Let's also remember these reviews from the same site...

Audience Au24 speaker cables...
“…you hear an orchestral cymbal just one time, with its immediate leading edge explosion of sound followed by a crystalline waterfall of winking stars dissolving into the background silence…”. Both versions of Au24 get that “leading edge explosion” right, but the new “e” cable is noticeably better at letting one hear that beautiful “crystalline waterfall of winking stars dissolving into the background silence”. It is really an awesome experience.

In my review of the Au24, I sort of copped out while describing the cables:
“I could say this ten different ways and possibly still not effectively communicate this cable's large improvement over any other speaker cable I have heard.” Audience Au24 “e” is not, quantitatively, a large change from Au24. But make no mistake, for a small increase in cost, the higher level of musical enjoyment is substantial. Natural selection or not, let me tell you that improvements on perfection are indeed possible. Thank you, Audience, for a new reference loudspeaker cable.

Slinkylins Cables...
The Slinkylinks cables, both interconnect and speaker cable, are fine performers. In my system, I preferred the relatively warmer sounding PS Audio cable, but the Slinkylink cables performed at a similar level of quality overall. If you are looking for a high performance cable that combines complete freedom from grain and high resolution with notable clarity and minimal distortion, the Slinkylinks cables are definitely recommended.

 

[pearsall001]

I am not sure it is entirely true. There is for example a fairly bad review of the Nuforce reference 9 amp (http://www.10audio.com/nuforce_ref_9v2se.htm)

I have also seen some other bad reviews of other amps, so bad reviews do exist. I do agree there are some good reviews of snake oil as well (sadly).

I read that same review before & I had to do a double take & reread it. I didn't believe what I had just read. They didn't like the NuForce at all. That is probably the first review that I read that told it like they heard it. Yet, other reviews are off the charts for NuForce. That's why we let our ears decide the final verdict.

Chart graphs, specs, & other measurement info are all important but don't necessarily equate to what the actual piece will sound like.

 

[Lordoftherings]

Bravo!

Interesting thing is that despite these clear technical compromises with class D design (or at least with ICEPower design), there are literally dozens of reviews (both here and in Europe) of various ICEPower-based amps and ALL of them are either very good or simply stellar.
Here are just a few reviews:
http://www.10audio.com/wyred4sound_st1000.htm
http://www.6moons.com/audioreviews/wyred/monos.html
http://www.ultimateavmag.com/amplifiers/808wyred/
http://www.positive-feedback.com/Issue39/wyred4sound.htm
http://www.6moons.com/industryfeatures/icepower/icepower.html
http://www.acoustic-reality.com/articles/eng_highfidelityreview.pdf
http://www.acoustic-reality.com/articles/eng_asp.pdf
http://www.audiophilia.com/wp/?p=1223
http://www.hometheaterhifi.com/power-amplifiers/594-bel-canto-s500-power-amplifier.html
http://www.hometheaterhifi.com/power-amplifiers/11-a-secrets-power-amplifier-review.html
http://www.hometheaterhifi.com/power-amplifiers/438-a-secrets-power-amplifier-review.html
http://www.6moons.com/audioreviews/eone2/1000.html
http://www.soundstage.com/revequip/belcanto_ref1000.htm
http://www.positive-feedback.com/Issue38/belcanto_ref1000.htm
http://www.avrev.com/home-theater-power-amplifiers/mono-amplifiers/bel-canto-e.one-ref1000-digital-mono-power-amplifier.html
http://www.stereotimes.com/amp041509.shtml
http://www.ultraaudio.com/equipment/bel_canto_e_one_ref1000.htm

There are more...

I am yet to read a bad review of these ICE amps. In these reviews these amps are compared to many linear amps and almost always favorably. If even cheaper linear amps are better based on some technical specs, why are all these reviews so highly positive? Even by random chance you would expect a share of bad reviews. Does it mean that these technical shortcomings are not really crucial for our sound perception? Or are all these reviewers simply wrong and they mistake different sound for better sound?

Well done Vlad. You did put some nice effort into this, and it is well appreciated.

Bob

 

[Lordoftherings]

Vlad, there have been some positive reviews of class D amps for sure, but be careful what you read, listen to the gear and form your own opinions. Purely subjective reviews do not have the same value as those that can back up the listening portion with measurements -- AH, Stereophile, Secrets etc. Positive Feedback and 6moons are well known for unabashedly praising esoteric products with no measurements to back them up.

Take a look at the review from 6moons of the Genesis (of the speaker fame) Reference amplifier, an amp that is built from fairly low cost DIY modules available from Hypex. This makes products from D-Sonic and W4S look like relative bargains. Genesis claims modifications that greatly improve sonic performance, given the premium price I would like to see the proof.

Now the Hypex modules perform well as reviewed by Hardware Analysis. To put this performance into context however, you would have to ask how a pair of $20K linear amps perform relative the the Hypex based Genesis?

There is ample data that shows that Class D amps do not reach the sonic performance of a traditional linear amp, including B&O's own spec sheets. The Absolute Sound did broad review of many class D amps in issue 166, November 2006, as did Suono (Italian Hifi mag) across two issues in June (N.393) and July/August 2006 N.394/395). These are the most complete reviews I have seen. Both came away with Class D being OK but not quite up to linear amp standards. I still have a class D amp on a short list for my new HT room, however I know that I am trading advantages in size, weight, heat and efficiency for a little sonic performance.

Good stuff Paul, I love The Absolute Sound; many reference articles there.

Bob

 

[buzzy]

What boggles my mind is some users of Class D amps think sonic nirvana has been achieved and current designs cannot get any better. I don't feel this way about any technology, especially one as infant as this.

That's a truism - of course there's room for improvement. But it's likely going to seem incremental and very modest compared to the jump that has been made to get to this point. The announced and partially released AX2 series of B&O amps are an example of that. The current B&O and Hypex designs (which have been around for a while) represent a remarkable combination of power, sound quality, size, and low power consumption. You say as much in the article. So it's not that surprising that people find these amps compelling.

I'd think you'd be more boggled by the uninformed comments made about Class D. Though I guess there's a lot of that on every topic.