Class-D or switching amps, any opinions on??

My problem is with resolution. As you said TACT stated resolution from PWM is 8 bit. Where do they get required extra resolution?

Kijanki, though it may seem counter-intuitive, reducing the quantization noise that results from limited resolution is mathematically the SAME as increasing the resolution, apart from any possible side-effects of the digital filtering processes. So they get the required extra resolution by the oversampling + noise shaping + dither processes that I referred to.

Keep in mind that limitation of resolution to a finite number of bits is mathematically identical to summing a noise component ("quantization noise") into the signal. If I recall correctly, assuming random error distribution (which is pretty much assured by applying proper dither), the rms quantization noise amplitude is equal to the lsb increment (in volts) divided by the square root of 12.

The oversampling allows most of the quantization noise to be shifted to higher frequencies than the audio information, where it can be filtered out with minimal impact on the audio. Dither randomizes the process to eliminate "deterministic errors," as the article indicates.

I believe that the other pwm applications you mentioned, delta-sigma converters, sacd, and dds, do the same thing.

Regards,
-- Al

Al - they do, but carrier frequency is almost 10x higher and resolution is 16-bit. SACD pulse width modulates at 2.8MHz - said to be equivalent to 20-bit on non-oversampling system. My analog class D amp (Icepower 200ASC) runs at about 500kHz with unlimited resolution. There is no quantization noise since it is not a sampled system.

I have been enjoying the Red Dragon Leviathan mono blocks.
They replaced Classe DR 8 monos, and Cary 300sei.

I have used them with Tanoy Arden,Merlin TSM MMX, and Ref 3A Grand Veena.

I have experienced all of the pros and none of the cons when people describe D amps.

Very satisfied and trouble free.
First amp I have ever left on 24/7.

10-25-09: Magfan
What is 'the new class D technology'? Who makes it? What makes it different?

If you go here you'll know as much as I do - except that I have heard about this elsewhere (an online discussion at one of "the' various sites).

I would like to know more...

Sigh, one more time. I have used SS (mosfets) and "Class D" amps (Tripath and Hypex), Class D is better. I have used a tube pre with both technologies. I would rather have a tube pre with a SS amp than a SS pre with a Class D. My old ears (61) say CD to SS pre to SS power just doesn't deliver. If you want a warm, more natural, musical sound; you are going to have a tube in the equipment chain, at least a tube DAC. Really good tube power amps are Really Expensive. The damping, power, clarity and tonal balance of power switching amps is within financial reach. They will faithfully amplify what they are fed; quality of input=quality of output. I believe Class D or power switching or whatever you want to call it is a better amplifying technology than Mosfets or Jfets. Are there SS amps superior to Class D? Yes, but the cost difference is, at least, a factor of 10 ($400=$4000).
This topic has been kicked around so many times, so I guess one more time can't hurt. Good listening for everyone.