Axiom Home Page Forums General Discussion Home Theater Know anything about these D-sonic amps?

Anyone use or know anything about these amps?? I’m particularly interested in the Magnum 1250-7, or possibly the Magnum 2500-7. I like the power split. 1250 – 250 X 3 / 125 X 4 ~ 2500 – 525 X 3 / 250 X 4 (ratings are at 8 ohm)

I have not heard of these, or this new “Ice Power” technology. They claim they do not need cooling fans or heat sincs.

Seeing how I’m looking at that buy-now-button for the A-1400 pre-buy, I might as well look and see what else it out there. These look very impressive at first glance.

http://www.d-sonic.net/

http://www.icepower.bang-olufsen.com/sw2093.asp

Mike,

I looked at the so-called ICEpower link and it is a lot of marketeering frankly. ICEpower is nothing more than a class D amplifier that incorporates negative feedback.

What they refer to as "conventional class D" is simply a class D amplifier with no feedback. What they refer to as ICEpower is a class D amplifier with negative feedback from the switching node and the filter node to ensure that the amp remains stable over a wide range of speaker load impedances.

I wouldn't be surprised if Axiom utilizes this same "dual feedback" mechanism in their A1400 architecture in order to enable the amp to be compatible with an extensive range of speakers. I am sure you know this but it's worth repeating for others: when evaluating amps, it's best to compare their specifications than fall victim to marketing hype. I know it's difficult to do that in this case because Axiom hasn't released comprehensive specs for the A1400 so Axiom better get cracking because it looks like the competition is around the corner .

One other thing after looking at the 2500-7. It's rated at 3X525W & 4X250W. That's a total of over 2500W. At about 70% efficient, that means you need over 3200W to power this thing. How do you get that out of one household circuit? Or am I misunderstanding something?

This reminds me of Carver's Sunfire amp that I ranted about a few weeks back .

Did you flip through the spec sheets? You have to download the PFD files. Too much information for my IQ to interpret. Plus, I’m no EE, so the specs are Latin to me. However, they seam to have a lot more information available for the technically competent that any other amp spec sheet I’ve seen before. I don’t think they are hiding anything.

I downloaded the specs for the ICEpower 1000 but it was such a nice day outside I decided to throw the football with my son .

So now I am looking at the power specs and I may just be as confused as you . I haven't looked at any other specs yet.

For power, there are FTC and EIA ratings. The EIA power is typically measured "mid-band" (usually 1 KHz) at 1% THD with a single channel operating into a specified load. The FTC rating requires the specified power to be maintained from 20Hz to 20KHz with no more than a specified level of distortion with both channels driven into a specified load. The FTC rating is more conservative and more reflective of the amp's capabilities under "real life" conditions. The EIA rating is useful for a 2 Ohm load because the FTC spec calls for the amp to be operating at full power for 5 minutes prior to measuring. Since 2 Ohms is right about where most protection circuitry is designed to activate, the amp will go into protection mode before the 5 minutes is up. Therefore most manufacturers specify an EIA rating at 2 Ohms.

This amp has an EIA rating of 1100W into 4 Ohms and 600W into 8 Ohms. It has a "cryptic" FTC spec of 150W into 4 Ohms from DC to 3KHz with no specified THD and no heatsink. This FTC spec doesn't mean much to me. Note that a 2 Ohm rating isn't given. Presumably the heat sink is the OEM's responsibility.

So if you were to ask me how this amp would perform with an M80, I'd have to use the EIA spec to give you an answer. So I'd say that it could source somewhere between 300W at maximum M80 impedance (~15 Ohms) and 1100W at minimum M80 impedance (~4 Ohms) at 1 KHz with no more than 1% THD. Although this sounds very respectable, I'd like to understand the FTC rating before passing any judgment.

As for the D-Sonic products, it appears to me that they are simply just passing on the ICEpower module specs to their consumers. I hope the A1400-8 specs are easier for us to interpret.

-------------- Revision to my post above ---------------

The bold portion should read:

So if you were to ask me how this amp would perform with an M80, I'd have to use the EIA spec to give you an answer. At 1KHz the M80 impedance is about 12 Ohms. So I'd say that it could source about 400W at 1 KHz with no more than 1% THD. Although this sounds very respectable, I'd like to understand the FTC rating before passing any judgment.

I just noticed that Rotel and B&W are using these "ice" amps along with other head liner amp companies. Cool. I wonder if Axiom is using them..... they sound simular in design. No heat sinc or fans.

http://www.icepower.bang-olufsen.com/sw2683.asp

From what I understand of the Axiom design, each channel has 1400W capability. ICEpower doesn't have a module like that.

Also, the ICEpower form factor is too big to fit into Axiom's 4" tall chassis.

Hi Mojo and all,

To clarify the differences between ICEPower modules and the new Axiom A1400-8 amplifier, I went to the source--Tom Cumberland, Axiom's chief R&D engineer and the Axiom A1400's designer. Here is Tom's response to my question on the ICEPower modules and our Axiom A1400-8:

"The ICEPower amplifier modules were developed at Bang & Olufsen in Denmark by a friend of mine. We even have two of the 250-Watt modules in our lab. They were developed in the late 1990s and early 2000 as a very efficient substitute for Class AB amplifiers. Bang & Olufsen recognized, as we did at Axiom, that the real benefit of Class D amplification is in high-power applications. They developed a 250-Watt and later a 500-Watt module. The design of the module itself was exceptional in its day. By today’s standards, it is still up there with the best of them. I have a great deal of respect for these modules. They make great ‘plug & play’ amps for companies that do not want to invest in the costly R&D needed to start from scratch, so to speak, in building a truly high-powered hi-fi amplifier.

"The B & O design has similarities to Axiom's in that it is really designed for high-fidelity applications, and not just for raw power output with no regard for high-fidelity criteria. However, here at Axiom we were looking to exceed what was available-- and what will be available--anytime soon. By using new silicon devices that were not available two years ago, we are able to exceed the power limits that even the ICEPower modules have. They stop at the 500-Watt mark due to the voltage and current requirements. But because of the newer parts we are using, we are able to exceed the voltage and current limits of older MOSFETs, thereby gaining incredible instantaneous power into any channel that needs it. This allows the music to dynamically peak without clipping into one or several of the loudspeakers without distortion. As testing our prototype amplifier has demonstrated, the limitations only then come in speaker compression, not in amplifier clipping. The sonic differences are quite noticeable. Clipping is very irritating, while compression is very livable."

Regards,

The ICEpower amps deliver a lot of power, run very cool, and require very little power. They are going to be my next amp.