Whose got best class D at this point?

my nuforce ref 9 SEs are working just fine for me, powerful enough for my speakers, fast, detailed, clear as a bell, and no problems with emf for me, waiting for my nuforce p-9 preamp.

I'd like to comment on class d amps on horns. I'm using a tact Millenium MKIII amp on my Omega DUO's which is highly modded.
The tact is quite different than most other amps mentioned here. It directly convert's pcm tp PWM. It is incredibly quite and even at extreme low volumes doesn't lose resolution which is important when using + 100 db efficient speakers.
Class d amps switching a constant voltage on and off. The tact does the same. it differs because it is adjusting thje volate which is beeing swicthed. Very smart. no volumke control in the signal path?
A friend who has the same modded Millenium compared against the latest Nuforce and said with exception of the bass makes them sound broken in comparison especially in the heights.
Just my 2 cents

In response to class D amps running Horns.

I am running Channel Islands D200 with Klipsch LaScalas and find them to be the best amps I've yet heard with these horns.

I've had the LaScalas for over 20 years and run them with numerous other amps, and many with great success, but none sounded as good as the D200s.

I would suggest that not all class D amps are equal...

Adman227, I'm no expert on amplification classes, but my limited understanding goes something like this:

Class A: The output transistors don't switch off and so current is always flowing through the transistors. Whatever current is not demanded by the speakers remains as a voltage across the transistors. This difference between current flowing and voltage across the devices is why Class A amps generate significant heat and are considred particularly inefficient.

Class B: Each output transistor operates for half of the sound wave (one for positive and one for negative). In this way, the amplifier does not have current constantly flowing through the transistors but rather only has current flowing through it dependent on their being an input signal. Pure Class B amplifiers are rare in quality audio due to the crossover distortion which occurs due to the transistors not being constantly conducting current.

Class A/B: The solution to crossover distortion in Class B in a far more efficient package than Class A is the Class A/B amplifier which usually has the output transistors constantly conducting a very small current. So the amplifier operates in Class A for the first few watts (could be more could be less, depending on how the amplifier is biased) because the output transistors are constantly conducting a current. As output levels are increased, the amplifier then operates as a Class B with the transistors "sharing" the waveform.

Class D: Also known as "switching amplifiers", the Class D amplifiers output transistors are either fully on and conducting or fully off and not conducting. The Class D amplifiers are extremely efficient because when the output transistor is switched off, there is high voltage across the transistor but no current is conducted and vice-versa when the transistor is switched on there is current flowing but no voltage across the transistor. The switching on and off of the output transistors can cause "switching distortion", however.

So having just re-read all that, I'm not too sure I've helped clarify anything at all. I would think the amps you listed (Rotel, Bryston, etc) are all Class A/B types.

I respectfully request those scientists and electrical experts to correct my definitiona as neccessary!

Thank you "Hens" for taking the time to explain this is great detail. Much appreciated.
Regards.