Oh how I wish Class D amps ...

"Nobody has mentioned the NAD M2,anyone had a listen to this one?"

No but it is on my want to hear list.

Realize that this is a true digital integrated that includes a Class D power amp and is all digital in front of that (except for analogue inputs that are converted to digital internally). So this is a slightly different but related beast.

How about the ARC DS225 or 450?

Hello Kijanki,

"It is often said that Icepower sounds good only with linear power supplies. On the other hand newest linear class AB amps from Jeff Rowland (one costing $46k) use switching power supplies. "

You are correct, Jeff Rowland developed his own highly regulated switching power supplies with PFC and show that this power supplies is the future for class A or A/B, ss and tube amplifiers.

We also have developed in 2008, very powerful swtiching power supplies with PFC abd fully regulated but we use it in our pro audio projects only as price/benefit analyses of moving it to Musician III with its linear power supplies show relatively little sonic benefits versus substantial price increase to cover the transition.

Refarding all other switching power supplies I am aware of - some like NuForce in their Ref 18 amplifier started to add electrolitic energy storage capacitors, This, if done right, should substantially improve current delivery and peak power delivery which in turn should improve sound.

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.