Attack of the Clone Amplifiers

[gene]

I agree with you there. I am interested, however, what can be perceived by humans and what is beyond perception.

I am right there with you. Hopefully over time as I get a chance to measure more of these amps, and do controlled listening comparisons, I can get a better picture of what is going on. So far I can tell you we can usually measure stuff we can't hear and we can usually hear stuff we can't measure, especially when it comes to loudspeakers. Correlating measurements and audibity is not a trivial matter.

 

[bborzell]

This question runs a risk of being a bit too far off topic, but since one of the posters referenced preferring "Pro Audio" amps in a home theater setting, I'll give it a shot.

Some time back, I lost a channel in my B&K surround speaker amp. While waiting for repairs, I looked around in the closet and found an old Pro Audio two channel rack amp that I had removed from my recording gear years earlier. I used it until the B&K returned from repair land.

I can't recall if there was any audible difference or decrement in surround speaker sound, but it got me to wondering about simply using Pro Audio amps in a home theater system. I contacted a few manufacturers and asked if there were any clear downsides to using a Pro Audio amp in this manner and got responses all over the map; from "not a problem" to "Pro Audio amps are designed for a different purpose, stay with more conventional HT designs".

Nothing specific; pretty much all anecdotal and no clear reference to what might be different from a design perspective.

Any thoughts on this?

 

[Dan Banquer]

More Links:

http://www.rothenberg.org/Phase/index.htm

http://www.dsprelated.com/dspbooks/filters/Phase_Distortion_Passband_Edges.html

http://mue.music.miami.edu/thesis/dkoya/chapter_2/chapter_2.htm

A long time ago on a planet far far away people decided that electronics should "get out of the way" and leave it to loudspeaker and room.

It appears that the planet in question has been either destroyed or on a very long vacation.

d.b.

 

[VladP]

I am right there with you. Hopefully over time as I get a chance to measure more of these amps, and do controlled listening comparisons, I can get a better picture of what is going on. So far I can tell you we can usually measure stuff we can't hear and we can usually hear stuff we can't measure, especially when it comes to loudspeakers. Correlating measurements and audibity is not a trivial matter.

I agree with you and I will be looking forward to your findings.

 

[VladP]

More Links:

http://www.rothenberg.org/Phase/index.htm

http://www.dsprelated.com/dspbooks/filters/Phase_Distortion_Passband_Edges.html

http://mue.music.miami.edu/thesis/dkoya/chapter_2/chapter_2.htm

A long time ago on a planet far far away people decided that electronics should "get out of the way" and leave it to loudspeaker and room.

It appears that the planet in question has been either destroyed or on a very long vacation.

d.b.

Thank you!!

 

[Dan Banquer]

For additional fun and games Vlad, Google the following:
Slewing Induced Distortion & Phase Deviations and Transient/Step Response in Amplifiers. That's for starters on non linear behavior in Amplifers as it pertains to this subject.
BTW: This is all very old and well known stuff in the EE world.
d.b.

 

[gene]

I can't recall if there was any audible difference or decrement in surround speaker sound, but it got me to wondering about simply using Pro Audio amps in a home theater system. I contacted a few manufacturers and asked if there were any clear downsides to using a Pro Audio amp in this manner and got responses all over the map; from "not a problem" to "Pro Audio amps are designed for a different purpose, stay with more conventional HT designs".

Yes and No. Most pro amps are designed for high power but not necessarily high fidelity. They tend to be noiser than home theater amps especially ones using fans, and switching power supplies to make them lighter weight and less costly. There is more to an amplifier than power just like there is more to a car than horsepower. I suppose you could use a race car on a city street but its probably not going to be very comfortable as a daily driver.

 

[jliedeka]

Thanks for writing this article, Gene. It was very informative. I can't wait to see a thorough review of one of these amps. I'm hoping Wyred4Sound will provide you with a review unit since they seem to to sell value products that mesh with AH's user base.

Jim

 

[Lordoftherings]

Better audio quality or not? That is the question.

This thread starts to be quite interesting.
Class D Amps with ICE modules, bring them on, so we have something new to evaluate compared to class A/B or Pure class A amps, or even class H.
Phase is indeed important in speakers & subwoofers, so as in amplifiers.
And frequency response with wide extension does have a benefit too, as it influences the frequencies that we can hear, and get the distortion way out of the audio range.
Is a subwoofer with class A/B amp built-in would have a more controlled low bass with better definition and accuracy than one with class D, regardless of total power output?
Are class D amplifiers or receivers main advantage only efficiency, smaller size and cutting costs?
From my over 40 years in Audio, at low power, a class A is ideal, and as the power raise, a switching A/B design is the way to go.
What is the percentage of class A/B right now on the market, including power amps, integrate amps and receivers, perhaps 80% or so? There must be a logical reason.
Does Home Theater is changing the game plan, compared to only 2-channel stereo serious listening?
Is more power in smaller compact design is the new wave?
What about the high quality of audio like Dolby TrueHD & DTS-HD MA?
Power vs Quality, or both?
I just recently listen to Jeff Beck "performing this week...live at Ronnie Scott's" on blu-ray. Wow! Very nice sound indeed in DTS-HD MA. Same for John Mayer "Where the light is", also on blu-ray. These live recordings sound fabulous in multichannel from my Onkyo805. They compete easily and even surpass SACD multichannel recordings; audio wise they are extremely satisfying, plus they give you a high definition picture on top of that. Here's my new high res. audio format for Music listening. Cannot ask any better. Blu-Ray all the way.
Will a class D receiver, like Pioneer Elite SC-05 or 07, will give me a better definition of sound than my class A/B Onkyo receiver?

What you guys think? What Gene think? I want to know. I want to learn more.

Cheers all,

Bob

 

[dsonic]

D-Sonic reply

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

Gene,

Please contact me regarding your review policies. I propose sending you my M1000S stereo amplifier to evaluate. We sell pure, unmodified ICEpower technology at the most reasonable price in the world at this time, $788/channel.

A few points:
1) The phase charts you show indicate that phase stays true up to 1KHZ. All of the connected articles showed that it became much more difficult to hear differences as the frequency advanced beyond this level, especially with real music. If also in a room, it was virtually impossible.
2) Should you get full power for full bandwidth? No, not if it adversely affects size, price, and performance. The present FTC continuous power ratings do not apply to class D. What is important is that they will provide speaker drivers with distortion free SPL's at levels most AB linear amps can only dream of. I believe no other commercially available home amplifier can match the 1000ASP in this category at this time. Why get hung up on B or C when you can jump directly to Z.
3) Your initial price estimates for building amplifiers might work in China. Here, I pay $50 for a stereo faceplate, $29 for a power cord, double your estimated chassis and labor cost. Components and wiring have doubled in the last year and B&O has raised their module prices. In our 7 channel units, component costs start to bite hard.

I agree with much of your main point regarding marketing strategies vs price. All I can say is look at those price per channel numbers and make your own decision. I might have some other comments on the issues discussed here later.


Regards,

Dennis
d-sonic.net

 

[AcuDefTechGuy]

The present FTC continuous power ratings do not apply to class D. What is important is that they will provide speaker drivers with distortion free SPL's at levels most AB linear amps can only dream of.

First, THANK YOU to Dennis for offering your ICE Powered module for a more in-depth Audioholics review!!!!!

I would LOVE to read this review of your module from Audioholics.

Second, could you please give an example or elaborate on this quoted statement?

 

[Chu Gai]

I'm also unaware of any FCC exclusions for Class D with respect to the conditions that power is measured under. I also thought that the usual warm up, preconditioning, full bandwidth, etc. specifically applied with respect to 2-channel consumer amplifiers. For vendors selling their wares in the US, isn't the above as well as emissions compliance is mandated by either regulations or laws.

 

[Dan Banquer]

I'm also unaware of any FCC exclusions for Class D with respect to the conditions that power is measured under. I also thought that the usual warm up, preconditioning, full bandwidth, etc. specifically applied with respect to 2-channel consumer amplifiers. For vendors selling their wares in the US, isn't the above as well as emissions compliance is mandated by either regulations or laws.

As some of us have observed; the FCC is far more interested in wardrobe malfunctions.
d.b.

 

[Chu Gai]

Well they had an interest in Behringer to the tune of a million dollars. The only malfunction was that he didn't rip the other one off too and then go for the money shot.

 

[dsonic]

full bandwidth clarification

I would LOVE to read this review of your module from Audioholics.

Second, could you please give an example or elaborate on this quoted statement?[/QUOTE]

AccuDef: In point 2) I stated that full power for full bandwith was not necessary if it adversely affected the performance of a class D amplifier. What I meant was that full power for full bandwidth as defined by the FTC protocol was not relevant for a class D unit.

If you look at page 6 of the data sheet referenced in the article you will note in the first row of the Audio Specifications (Po = power out) that by class D standards the 1000ASP does indeed meet its requirements for the 10HZ to 20KHZ bandwidth at 525W/8ohm and 1100W/4ohm.

I believe the real test is ultimate SPL at the speaker and the amount of dynamic headroom available at these high levels. With ICEpower, the last watt is just as clean as the first. You can play at levels that exceed the live, acoustic power of some instruments and not realize how extreme that level is until you go outside and find out you are entertaining the neighborhood. The benefits of this wide dynamic range are appreciated long before you reach these high levels.

Regards,

Dennos
d-sonic.net

 

[gene]

I would LOVE to read this review of your module from Audioholics.

Second, could you please give an example or elaborate on this quoted statement?

AccuDef: In point 2) I stated that full power for full bandwith was not necessary if it adversely affected the performance of a class D amplifier. What I meant was that full power for full bandwidth as defined by the FTC protocol was not relevant for a class D unit.

If you look at page 6 of the data sheet referenced in the article you will note in the first row of the Audio Specifications (Po = power out) that by class D standards the 1000ASP does indeed meet its requirements for the 10HZ to 20KHZ bandwidth at 525W/8ohm and 1100W/4ohm.

I believe the real test is ultimate SPL at the speaker and the amount of dynamic headroom available at these high levels. With ICEpower, the last watt is just as clean as the first. You can play at levels that exceed the live, acoustic power of some instruments and not realize how extreme that level is until you go outside and find out you are entertaining the neighborhood. The benefits of this wide dynamic range are appreciated long before you reach these high levels.

Regards,

Dennos
d-sonic.net[/quote]

Dennos, no ICE amp can do full power bandwidth into a 4 ohm load to my knowledge and according to the data sheet. I am however interested in reviewing your amp. I am backlogged a bit now but can schedule this sometime in late June or early July. Please PM me your contact info. Thanks for participating in our thread.

 

[dsonic]

FTC and FCC

I'm also unaware of any FCC exclusions for Class D with respect to the conditions that power is measured under. I also thought that the usual warm up, preconditioning, full bandwidth, etc. specifically applied with respect to 2-channel consumer amplifiers. For vendors selling their wares in the US, isn't the above as well as emissions compliance is mandated by either regulations or laws.

Chu Gai,

I believe the Federal Trade Commission (FTC) handles issues regarding amplifier power and the Federal Comminications Commission (FCC) handles issues regarding RFI and EMI emissions.

 

[Chu Gai]

You're correct Dsonic. Now, how is it that your outfit complies with both?

 

[dsonic]

data sheet does support full bandwidth into 4ohms

Dennos, no ICE amp can do full power bandwidth into a 4 ohm load to my knowledge and according to the data sheet. I am however interested in reviewing your amp. I am backlogged a bit now but can schedule this sometime in late June or early July. Please PM me your contact info. Thanks for participating in our thread.[/QUOTE]

Gene,

The data sheet clearly states that the 1000ASP will output 1100W/4ohms, 20HZ to20KHZ. You have my contact info now: d-sonic.net. Let me know when you can do the review and we can make this happen.

Thanks for your welcome to the thread.

Dennis
d-sonic.net

 

[randyb]

You're correct Dsonic. Now, how is it that your outfit complies with both?

Chu, I think Dennis Murphy (of Salk fame) helped draft the FTC rules on power specs as he is a PHD economist (besides a longitme DIY crossover guy) at the FTC. You might see what he has to say about Class D amps and ratings and compliance.

http://www.ftc.gov/opa/2000/12/amprule.shtm