Attack of the Clone Amplifiers

[admin]

It’s been a few years since the release of our controversial article called “Attack of the Clone Processors”. Engineering a product from the ground up, especially one as complex as a switching amp, takes time and money with the end result often not being as good or cost effective as what can be bought off the shelf like these ICE modules from Bang & Olufsen. I can count the number of manufacturers producing their very own Class D designs and still have a finger left to point at all the copycats. Overall this seems to be a good design approach for manufacturers unwilling or unable to do their own developmental work if cost and full disclosure of performance is kept in check. It’s up to you the consumer to decide if paying a premium price for name brand, exotic accessory parts and cosmetics is worth the investment. Just don’t let anyone tell you that regardless of price, you are buying anything other than a clone amplifier, albeit a reasonably well engineered one.

Discuss "Attack of the Clone Amplifiers" here. Read the article.

 

[Lordoftherings]

Cool (ICE) stuff.

Very cool (ICE) review Gene.

Class D amplifiers seem appropriate for powering subwoofers.
But is it sufficient enough, even if they are very efficient, to be used as the main power for all the frequencies up to SACD limits?

Are they good enough for 96 or 192khz, as a faithful reproduction from certain audio formats?

Is the Pioneer Elite SC-07 (with class D, ICE amp modules) lacking when ask to deliver into 4ohm loads?

Bob

 

[Dan Banquer]

Very cool (ICE) review Gene.

Class D amplifiers seem appropriate for powering subwoofers.
But is it sufficient enough, even if they are very efficient, to be used as the main power for all the frequencies up to SACD limits?

Are they good enough for 96 or 192khz, as a faithful reproduction from certain audio formats?

Is the Pioneer Elite SC-07 (with class D, ICE amp modules) lacking when ask to deliver into 4ohm loads?

Bob

To answer the above questions I would recommend that you pay attention to the data sheets linked to theis article. Please pay close attention to the frequency response vs. phase graphs.

I have read this article a couple of times and I find myself still LMAO.
d.b.

 

[rnatalli]

I had an Emotiva DMR-1 which uses D2Audio Class D amps and I could barely tell a difference between it and the LPA-1. That would probably change if I hooked up terribly inefficient speakers and cranked them.

 

[Chu Gai]

I've noticed that none of the ICE based amps that are sold in the US have had their finished products tested or certified to meet FCC Part 15B for unintenional radiators of EMI/RFI emissions. When I called Bel Canto the person I spoke with stated that they do meet this requirement but I've not seen the requisite information in their manuals. I understand that the modules are said to meet the requirements but that's the modules and not the finished product. Kind of like saying our power cords use UL listed materials but the actual cord was never submitted to testing. So, given that not too long ago, Behringer, who had imported a slew of products into the US which had CE listings but no FCC ones, was ordered to pay $1,000,000 in fines, aren't each and every manufacturer not only violating US law in this regard but also opening themselves up to fines? Thoughts?

 

[AcuDefTechGuy]

I'm sure these ICE Powered Amps are nice...

...But I was thinking of getting FIVE of the UGLY Behringer EP4000 amps, Bridge them, and get 4,000 WATTS RMS @ 4 ohms, 20Hz-20kHz, & 1% THD Per Channel...

And then hide them on the very bottom shelf.

 

[VladP]

I agree that the manufacturers of clone amps should be more open in description of their products and that they use B&O modules. I must say that some manufacturers like Wyred 4 sound are already fairly open about it and they convey exactly the same message - why pay more for the same technology. They do claim that their modifications separate their amps from the crowd and it remains to be verified.

Lack of independent measurements in these amps is disturbing and Audioholics don't help much with that - they reviewed Seymour amp and DID NOT provide any measurements - the question is why?

Many manufacturers claim that they modify their products and these modifications result in audible changes - criticisms of these claims in this article are not very good (IMO) and there are NO data presented to either refute or verify such claims. Measurements could be a good start. Instead of providing measurements, only verbal skepticism is provided. Until somebody actually directly compares these amps and fails to document claimed differences using solid scientific methodology, it remains possible that these audible differences do exist.

The article referenced at the bottom by HIFICRITICS is a clever combination of some cherry-picked facts mixed with subjective and unsupported by anything statements (e.g. below average tremble, average bass quality, listener fatigue, etc.) intended to confuse the reader and to push a certain agenda. There are plenty of other similar subjective evaluations by various hifi reviewers that are exactly opposite to those presented by hificritics so why should we believe just one of them? There are no tests or measurements of specific amps that validate his claims.

It would be useful to include some comments by engineers who actually design class D amps (why not ask Dr. Karsten Nielsen for his comments? He designed his ICEPower amps for his PhD dissertation, which is actually available at the B&O website). I remember reading something by the Axiom amp designer and he was actually quite positive about ICE amps and stated that they are still at the top of the game.

 

[bandphan]

I'm sure these ICE Powered Amps are nice...

...But I was thinking of getting FIVE of the UGLY Behringer EP4000 amps, Bridge them, and get 4,000 WATTS RMS @ 4 ohms, 20Hz-20kHz, & 1% THD Per Channel...

And then hide them on the very bottom shelf.

But it so dosent fit the rest of your preppy gear serious though wyred or dsonic fit the mold without failure and the goldmound 5kw at the price of a small house would drive those DTs to levels that would make most bleed, ears that is. Are new speakers in order to help with the power load ?

 

[AcuDefTechGuy]

But it so dosent fit the rest of your preppy gear serious though wyred or dsonic fit the mold without failure and the goldmound 5kw at the price of a small house would drive those DTs to levels that would make most bleed, ears that is. Are new speakers in order to help with the power load ?

Naah, I'm just messing around.

I'm quite content with the 150-watts RMS Per Channel, 20Hz-20kHz, 0.05% THD, 8 ohms, Denon power.

The highest volume I've actually used was -16 dB, and I wasn't even in the room.

I was eating in the dinning room, which is like 1,000 ft away.

 

[lsiberian]

Naah, I'm just messing around.

I'm quite content with the 150-watts RMS Per Channel, 20Hz-20kHz, 0.05% THD, 8 ohms, Denon power.

The highest volume I've actually used was -16 dB, and I wasn't even in the room.

I was eating in the dinning room, which is like 1,000 ft away.

This my friends proves these amps are unwise investments IMO.

If you need real power get pro amps. The market is much more competitive and you will get more bang for the buck. You could drive a home theater completely with 3 Behringer EPs. Including a passive sub. That's around 750 toss in the DCX 2496 and for 1000 bucks you have a 5.1 channel Amp with eqing, and crossover capabilities.

In reality most of us our fine with even a mid fi amps power.

 

[VladP]

To answer the above questions I would recommend that you pay attention to the data sheets linked to theis article. Please pay close attention to the frequency response vs. phase graphs.

I have read this article a couple of times and I find myself still LMAO.
d.b.

Could you please point out for me reviews of other power amps that include phase graphs? I checked a few Audioholics reviews and I did not seem to find any graphs similar to the one presented for the ASP1000 ICE module. I would like to see similar graphs for other amps.

 

[Dan Banquer]

Could you please point out for me reviews of other power amps that include phase graphs? I checked a few Audioholics reviews and I did not seem to find any graphs similar to the one presented for the ASP1000 ICE module. I would like to see similar graphs for other amps.

With linear amplifiers it really wasn't necessary because the phase linearity essentially folowed the frequency response. Flat frequency response gave you a linear non varying phase response.

As to your earlier post on measurements I see no reason to test every ICE amp that comes to market. If the ICE amp has NOT been modified on the original board than the only variations one might have is grounding to the chassis and the input and output connections.

If you want to get picky here each ICE amp will measure differently, but the measurements should be within the manufacturers parameters and the variation will be measureable, but the real question is will it even be remotely audible. I think not.
d.b.

 

[AcuDefTechGuy]

I see no reason to test every ICE amp that comes to market.

I agree. But was there measurement on ONE ICE AMP done by Audioholics?

Did I miss it like usual?

 

[Dan Banquer]

I see no reason to test every ICE amp that comes to market.

I agree. But was there measurement on ONE ICE AMP?

Did I miss it like usual?

Yep you missed it, there is a link to the data sheet from B&O in the article.
d.b.

 

[VladP]

I see no reason to test every ICE amp that comes to market.



Yep you missed it, there is a link to the data sheet from B&O in the article.
d.b.

NO, that link is to the B&O measurements. The question was about independent measurements. Audioholics only did Pioneer which used modified modules, not the standard ones.

 

[VladP]

With linear amplifiers it really wasn't necessary because the phase linearity essentially folowed the frequency response. Flat frequency response gave you a linear non varying phase response.

As to your earlier post on measurements I see no reason to test every ICE amp that comes to market. If the ICE amp has NOT been modified on the original board than the only variations one might have is grounding to the chassis and the input and output connections.

If you want to get picky here each ICE amp will measure differently, but the measurements should be within the manufacturers parameters and the variation will be measureable, but the real question is will it even be remotely audible. I think not.
d.b.

First, it would be nice to verify ICE Power measurements by an independent party. It has not been done.

Second, you have no idea what exactly these other companies did to the modules and they will probably not tell you the entire story if they want to keep it confidential. They do claim sound differences; you can remain skeptical or you can test their claims. I have been doing and teaching science for the last 30 years and so I prefer tests to hand waving.

If the company does not claim any modification, then I agree that there is no reason to test, but when differences are claimed...

Audioholics tested Axiom D amp but I did not see phase response graph there. Are these amps immune from the same problem?

What evidence is there to suggest that -50 degrees phase shift at 20KHz produces an audible difference in sound?

Also, this phase shift has nothing to do with amplifying hi fidelity recordings (SACD). These recordings have high sampling throughout the entire range.

 

[Dan Banquer]

First, it would be nice to verify ICE Power measurements by an independent party. It has not been done.

Second, you have no idea what exactly these other companies did to the modules and they will probably not tell you the entire story if they want to keep it confidential. They do claim sound differences; you can remain skeptical or you can test their claims. I have been doing and teaching science for the last 30 years and so I prefer tests to hand waving.

If the company does not claim any modification, then I agree that there is no reason to test, but when differences are claimed...

Audioholics tested Axiom D amp but I did not see phase response graph there. Are these amps immune from the same problem?

What evidence is there to suggest that -50 degrees phase shift at 20KHz produces an audible difference in sound?

Also, this phase shift has nothing to do with amplifying hi fidelity recordings (SACD). These recordings have high sampling throughout the entire range.

I'm going to be blunt and directly to the point here. I don't mean to be rude so don't take it that way.
A simple visual inspection between a ICE amp directly from B&O and the ICE amp from whoever will tell you 99% of what you need to know. The rest has been outlined in a previous post.

The phase shift issues and slewing induced distortion issues were investigated rather thoroughly back in the 70's and 80s. If you wish to research them please feel free to do so as I am not going to spoon feed anyone on issues that were resolved some thirty years ago.

This is what I truly "love" about audio. Things that were resolved years ago get recycled again to the public hoping that they either forgot, never learned or were never aware of as the issues were considered dead some thirty years ago.
It's a curse for us old farts.
d.b.

P.S. If you can find an SACD test disc, try measuring the phase shift in the audio band in the player. Or better yet get a Phillips CD1 test disc and measure the phase shift on the typical CD player. Let us know if you can find any phase shift in the audio band.
Do you think there might be a reason for that?

That's a rhetorical question Vlad.

 

[VladP]

I'm going to be blunt and directly to the point here. I don't mean to be rude so don't take it that way.
A simple visual inspection between a ICE amp directly from B&O and the ICE amp from whoever will tell you 99% of what you need to know. The rest has been outlined in a previous post.
The phase shift issues and slewing induced distortion issues were investigated rather thoroughly back in the 70's and 80s. If you wish to research them please feel free to do so as I am not going to spoon feed anyone on issues that were resolved some thirty years ago.
This is what I truly "love" about audio. Things that were resolved years ago get recycled again to the public hoping that they either forgot, never learned or were never aware of as the issues were considered dead some thirty years ago.
It's a curse for us old farts.
d.b.
P.S. If you can find an SACD test disc, try measuring the phase shift in the audio band in the player. Or better yet get a Phillips CD1 test disc and measure the phase shift on the typical CD player. Let us know if you can find any phase shift in the audio band.
Do you think there might be a reason for that?
That's a rhetorical question Vlad.

I am sorry but the auditory issues you were talking about have not been resolved in any useful scientific ways. I don't want to be rude as well, but anything published in a non-peer-reviewed publications have no scientific merit. All of these "studies" published in audio journals do not really qualify as good science. I would also think that the guy who designed the ICE modules is a competent engineer and not an amateur; after all he was awarded a PhD for his work.

I understand that you don't want to "spoon feed" anybody but unless you reference a peer-reviewed publication dealing with these issues, I remain skeptical about your "old facts", sorry. I guess I'll do more research, but for now everything objective I've read don't agree with most subjective criticisms of ICE amps.

 

[gene]

Second, you have no idea what exactly these other companies did to the modules and they will probably not tell you the entire story if they want to keep it confidential. They do claim sound differences; you can remain skeptical or you can test their claims. I have been doing and teaching science for the last 30 years and so I prefer tests to hand waving.

If the company does not claim any modification, then I agree that there is no reason to test, but when differences are claimed...

Audioholics tested Axiom D amp but I did not see phase response graph there. Are these amps immune from the same problem?

What evidence is there to suggest that -50 degrees phase shift at 20KHz produces an audible difference in sound?

Also, this phase shift has nothing to do with amplifying hi fidelity recordings (SACD). These recordings have high sampling throughout the entire range.

I will be reviewing an ICE 1000ASP sometime soon once I get my hands on one, and assuming one of the clone manufacturers will be willing to send to me

As for modifications to the 1000ASP module, very little can be done to them which was the point of my article that was obviously missed. Aside from adding some minor filtering, adding fancy connectors, and wiring, there is nothing left to do other than clever marketing.

B&O shows phase vs frequency response in the data sheet which I suggest reviewing. If a linear amp exhibited similar phase response, you could be assured it would be slammed by all of the audio critics capable of measuring them. This is a problem with all Class D amps b/c of the output filter which hopefully overtime will become less problematic as the switchers get faster and the LPF gets moved up higher into the frequency band.

Whether or not the phase shift is audible depends on how good your gear, room and ears are. We are dealing with objective measurable facts about these amps right now, not subjective auditory results regardless of how some users of this amp feel how it sounds.

I also suggest reading this article we wrote that deals with phase distortion audibility:
http://www.audioholics.com/education/acoustics-principles/human-hearing-phase-distortion-audibility-part-2

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.

 

[VladP]

I will be reviewing an ICE 1000ASP sometime soon once I get my hands on one, and assuming one of the clone manufacturers will be willing to send to me

As for modifications to the 1000ASP module, very little can be done to them which was the point of my article that was obviously missed. Aside from adding some minor filtering, adding fancy connectors, and wiring, there is nothing left to do other than clever marketing.

B&O shows phase vs frequency response in the data sheet which I suggest reviewing. If a linear amp exhibited similar phase response, you could be assured it would be slammed by all of the audio critics capable of measuring them. This is a problem with all Class D amps b/c of the output filter which hopefully overtime will become less problematic as the switchers get faster and the LPF gets moved up higher into the frequency band.

Whether or not the phase shift is audible depends on how good your gear, room and ears are. We are dealing with objective measurable facts about these amps right now, not subjective auditory results regardless of how some users of this amp feel how it sounds.

I also suggest reading this article we wrote that deals with phase distortion audibility:
http://www.audioholics.com/education/acoustics-principles/human-hearing-phase-distortion-audibility-part-2

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.

Sorry, but I have not missed this information, I just did not find it convincing yet. I am well aware of the graph with phase shift and I am trying to investigate this more.

I am a biologist and so I do not consider auditory results subjective if proper testing is done. I would not argue about measurable facts - I agree with you there. I am interested, however, what can be perceived by humans and what is beyond perception.