Oh how I wish Class D amps ...

Can someone write an explanation of Power Factor?

In the case of power supplies, do you try to make the power supply look like a resistor to the power company OR the amp look like a resistor to the power supply? I don't know that a pure resistive speaker is possible.

Spectron,

Switching power supply offers many advantages such as ripple that is easier to filter out, voltage that is line and load regulated and transformer that can deliver same power at high frequency at 1/10 of size. The problem here is that SMPS got bad rap from designs utilizing them for the size and cost and not for the quality. Looking from perspective of manufacturers - why to develop SMPS while 90% of people believe that it is no good. Only very brave that already established their name like Rowland or Linn are not afraid to use SMPS in class AB amplifier.

Claim that class D amp work better with linear supplies is in a sense illogical since SMPS is class D with fixed voltage (that's how class D was invented). Most likely implementation of given type of supply is the key. Icepowers in REF1000M benefit from extra capacitors, according to reviews, but my tiny Rowland 102 keeps composure (having regulated supply) even under long heavy orchestral peaks.

Question to you. I read some of the Karsten Nielsen doctoral work and understand a little nature of the beast. Modulator is a little similar to Sigma Delta converters what doesn't surprise me since this idea (using byproduct of sigma delta) was already used in things like SACD.
What is different in Spectron amps? I heard a lot of good things but wonder if they share the same principle. I'm not asking of course for any design details, just adantages in general.

Timtim, I'll back you up. I had the McCormack DNA 500, the W4S ST 1000 (twice), and currently the Cary A306 Class D amp. The DNA 500 was the sweetest sounding solid state amp I've owned with the most outstanding upper end I heard with the speakers I owned at the time. Sonically, much more refined than the Wyred, and the Wyreds are good. But considering the price difference, the Wyred ought to be outclassed by the DNA 500.

Foster_9 .... I appreciate the love LOL. Of course this is the world of high end audio we are discussing, and many are quick to get upset if their apple cart is tipped slightly.
Regardless of what anyone may think, I truly have NO adgenda to bash Class D ... and I will promise this : The day I hear a Class D amp that matches the sonics of the better Class A A/B amps ... I will buy it on the spot.
I would love to downsize, but I won't downgrade ;-)

Tim,

If you want Class D to sound good to you bad enough, maybe try building your system around a Class D amp of choice.

That would give you a better chance than plugging one into what you have currently and like and expecting that it will sound the same or better.

I went Class D because it fit the bill perfectly for what I needed in my rig at the time, especially the big full range power hungry OHMs that mainly benefit from the juice. So I too have a basis to compare.

The amps sound great to me on the Dynaudio monitors as well (hard to fault in any way for their size), but for those alone there are many amps that can fit the bill.

Most speakers I have heard that use ribbon tweeters would probably benefit from an A/B amp like the McCormack or similar than most Class D amps I suspect.

My expectation is most Class A/B amps in this discussion will tend to have a hotter top end than CLass D, at least Icepower. That is one difference I notice between the two.

Of course, different people hear the top end differently and that also changes with age which can also be a factor in what kind of amp sounds best.

You are making a mistake by dissing all Class D amps categorically though just because you like the sound of others in your system.

As has been pointed out, all amps are different and will have different perceived strengths and weaknesses.

My ears tell me Class D amps can be in the same league as their older brethren already these days but YMMV.