Interesting PWM amplifier thread (ICE vs UcD).

mac · « **on:** 25 Feb 2005, 07:36 pm »

diyAudio PWM ICE vs UcD thread: http://www.diyaudio.com/forums/showthread.php?s=&threadid=51548

Some good information there for those interested in the technology. I found Dan Fraser's comparison comments very illuminating.

muralman1 · « **Reply #1 on:** 25 Feb 2005, 08:15 pm »

Hello Mac,

I should have paid attention to your Fraser prompt. It would have saved me some boring banter reading.

As to Fraser's comments, I can agree to a qualified yes. I haven't heard his ICE amp. I know, from experience, ICE amps can sound very different from one another.

There are a number of Apogee users happily putting together their own UCD amps. I am eager to hear their verdicts. There was a short while where some users tried their hand at ICE amp building. To the last one, all those amps died on the vine.

Hoorah for UCD being more DIY friendly.

mac · « **Reply #2 on:** 25 Feb 2005, 09:10 pm »

Quote from: muralman1

It would have saved me some boring banter reading.

It's refreshing to read some objective statements about the ICE modules for a change.

This is an interesting time vs power graph that was posted off of the B&O website: http://www.diyaudio.com/forums/attachment.php?s=&postid=577113&stamp=1108595665 It shows that the ICE module cannot produce anywhere near full power at high frequencies w/o damaging itself. This is what Dan was referring to in his post.

Here's some of the other "borning banter" that I found interesting about the ICE modules:

muralman1 · « **Reply #3 on:** 25 Feb 2005, 09:44 pm »

That would mean, as I turn up the power servicing my .8 ohm speakers (near dead short) my amps would exhibit a drastic drop in fidelity that would be easy to hear. They don't.

mac · « **Reply #4 on:** 25 Feb 2005, 09:59 pm »

Quote from: muralman1

That would mean, as I turn up the power servicing my .8 ohm speakers (near dead short) my amps would exhibit a drastic drop in fidelity that would be easy to hear. They don't.

No, it has nothing to do with load or a "drastic drop in fidelity". It has to do with delivering power at full bandwidth. I thought the graph and the explanations in the thread were clear.

muralman1 · « **Reply #5 on:** 25 Feb 2005, 10:10 pm »

It would seem to me that if my speakers are getting less power over bandwidth with increase of power, then I would hear it. If I can't hear it, what is your point?

I've been running my amps at what would be amp suicidal levels for half a year.

mac · « **Reply #6 on:** 25 Feb 2005, 10:29 pm »

Quote from: muralman1

I can't hear it, what is your point?

If your program material is limited in high frequency content you may not have trouble (or hear it). Using a purely resistave speaker is probably helping your cause too. If you want to replicate the noted problem feed a 20kHz sine wave into your amp and raise the power level to 20w. If what the manufacturer states is true you should smell some odd odors being emitted from your amplifiers. As Dan pointed out, it's unlikely (and fortunate) that your amplifier will be required to deliver 20w at 20Khz under normal conditions.

muralman1 · « **Reply #7 on:** 25 Feb 2005, 10:51 pm »

I have been going through the ICE white papers. There is a lot of it. So far, I haven't run across that graph.

The material I am running through my speakers is as wide as the music scape. There are H2O amps running a wide variety of speakers. So far, no one has complained of smoking amps, or highs falling off.

mac · « **Reply #8 on:** 25 Feb 2005, 11:09 pm »

Quote from: muralman1

I have been going through the ICE white papers. There is a lot of it. So far, I haven't run across that graph.

http://www.icepower.bang-olufsen.com/graphics/powerhouse/user_graphics/pdfs/ICEpower250ASP_datasheet_1-2.pdf

See Fig. 11 & 12

muralman1 · « **Reply #9 on:** 25 Feb 2005, 11:46 pm »

OK

first of all, that white paper is for the ICE 250 ASP module.

Secondly, I can see by it's specs, it is quite different than the 500A, which the H2O is made with. I don't know of any HiFi amps being made with the 250ASP.

Are you going to be able to attend the New York Home Electronics Show in late April? The H2O Sigs will be powering Analysis speakers.