Current amp vs Voltage amp

" Full range, quality high efficiency speakers tend to be big and expensive.

I think you have blame the laws of physics for that!!! "

WHo better to blame without a dispute? :^)

Of course, Atmasphere's claim that negative feedback always makes an amp not sound like music as always is highly debatable, though he certainly backs up what he says with his products by not using NF.

The consensus answer to the NF issue seems to be that the results are a function of how it is done, with global feedback being more problematic than local.

My observation from listening and reading on teh topic is that good Class D switching amps seem to have a good NF implementation that makes it a non issue in terms of sounding "like music" or more like a good tube amp. Of course, what music really "sounds like" is highly subjective anyhow, so arguing about it is probably a moot point. Each experienced audiophile knows what does or does not sound like music or not to them.

I think Atmasphere and I do agree though from past discussions that one of the best indicators that things are working well is when turning the volume up sounds good and the high volume does not call attention to itself and is best indicated mainly by its volume relative to other sounds, like people talking, etc., and a bad NF implementation would seem to work against that goal.

IME, there is wisdom in what Ralph says about musicality and distortion. As I mentioned above, after switching output tranny taps, I think the midrange "forwardness" of my speakers has been tamed somewhat and bass seems more honest and extended.

And as far as turning up the volume, I do not detect any break-up or audible distortion. However, to be fair, when the SPL get's really high, my ears hurt. So what's the point of that exercise?? ;>')

As a point of scientific interest, I am curious how my speakers would perform if FR was measured in an anechoic chamber. But as Mapman said, and I agree with him, musicality has a significant subjective element to it.

Heck, even if my rig was ruler flat as proven in an anechoic chamber and my room didn't add any coloration, some recording are so bad, I think I'd prefer listening to pure distortion. LOL. Lately, I've been trying to get my hands on old London LPs. Many sound pretty good. OTOH, I've picked some LP dogs that are so bad, the neighborhood dogs howl. And I don't think that's because of NF or impedance peaks or negative phase angles. Some recorded music just stinks.

Great thread. I thank everyone for their terrific comments.

HEy, look, if it weren't for fretting over how well every technical detail of one's system is working in theory compared to others, what else would one do? Listen to music and find out, maybe?

05-09-13: Swampwalker
I'd love to hear Atmasphere and Almarg comment about how that type of amplifier's inherent electrical characteristics interacts w speaker loads.

Hi Michael,

I'm not especially familiar with Class D amplifiers. But in terms of output impedance they are of course firmly in the voltage source camp, with some of them having extraordinarily low output impedances/high damping factors. In terms of feedback, I don't have a particular feel for how much negative feedback most of them use, but I'd imagine that it is not insignificant in most cases.

An exception would apparently be the ARC amps that have switching output stages. Those are described as using no global feedback, and are spec'd as having 1% THD. Which would seem to raise the possibility that their behavior is somewhat tube-like.

Also, the Spectron writeups on their Musician III indicate that although negative feedback is used its adverse effects are claimed to be essentially eliminated as a result of the fact that transit time (aka propagation delay) through the signal path is exceptionally fast. I see no reason to doubt that claim.

As I say, though, I have no particular knowledge of the degree to which feedback may be employed, and the degree to which it may be an issue sonically, with Class D in general.

05-09-13: Bombaywalla
"In the Power Paradigm the box design puts the peak at a lower frequency to take advantage of the extra energy- but again netting fairly flat frequency response, but with the additional benefit of bass extension, which might well be up to half an octave."
Atmasphere, what does this mean? The box resonance peak is where it is. How does the Power Paradigm amplifier move that peak to a lower frequency?

I believe that Ralph was referring here to speakers that are designed per power paradigm principles, not to amplifiers. One of his underlying points is that both must be designed in accordance with the same paradigm, if they are to work well with each other.

05-09-13: Bifwynne
I've picked some LP dogs that are so bad, the neighborhood dogs howl. And I don't think that's because of NF or impedance peaks or negative phase angles. Some recorded music just stinks.

Truer words were never spoken :-)

Best regards,
-- Al

"I've picked some LP dogs that are so bad, the neighborhood dogs howl. And I don't think that's because of NF or impedance peaks or negative phase angles. Some recorded music just stinks."

No doubt.

Personally in my audio "journey" I have been in places in the past on occasion where few recordings seemed worth listening to. Nowadays, no two sound the same, and some are still barely listenable but the vast majority sound good enough for me to enjoy, especially if one takes pleasure in the variety of sounds a recording might deliver rather than futilely attempting to make them all sound similarly good.

FWIW, I use an ARC tube pre-amp and a Bel Canto Class D amp. There is a lot to be sid about pairing a tube pre-amp with a good Class D amp, if a tube amp is not what the speakers ordered.

So my conclusion is that the devil is in the details and the details are what will swing you one way or the other, for better or for worse.

As the great scholar and musician Frank Zappa once said, "you are what you is". Very true when it comes to recordings.