bel canto and wyred 4 sound

I believe if you check the forums, you might find some info on this. Its been discussed a few times.

Riley is correct about there being many forums about class d amplification, both positive and negative. I have been using class d for about five years. I have upgraded three time using the latest that Bel Canto offered. I can't tell you which brand to purchase. If you do put one in your system please give it a chance to break in. The Bel Canto REF500m I have now is still improving after eight months use.
Over the years I have owned many tube and solid state amps.
I took the plunge and glad I did.

Just purchased the Wyred 4 Sound STI500 after being very satisfied with their DAC1 and now DAC2. It hasn't fully broken in yet, but so far I am very impressed. I have Magnepan 1.7s and the STI500 has plenty of power with a very smooth sound. As it is breaking in, I am hearing more details.

Don't know about the Bel Canto. I purchased the Wyred 4 Sound STI500 based on quality materials in the construction, great reviews and terrific success with their DAC. It seemed to hit the sweetspot in price vs. performance.

The unit is very easy to use and very flexible. Highly recommended but give it PLENTY of time to break in - 200 hours, at least. When you do, you will love the sound with the Magnepan loudspeakers.

It's going to boil down to a lot of factors. I have owned a few class D amps, in fact currently own a pair of Ref 1000 by BC. In comparing the class D amps over the years, in evey comparison I have made to my class A amps (which have traditionally been Krell (4), Pass (2) or M. Levinson (3), but others as well), I have preferred the class A amps.

Across the board, my preference has been and continues to be class A. But, the class D amps have gotten gradually a bit better with each new generation - but still haven't proven to me to be top performers.

I'd look for a used Bel Canto over the W4S, but that is just me. I know W4S has a lot of proponents. I can't say from experience that you will notice much of a difference. The class D amps always made me feeling as though I was just missing something in the performance and that I couldn't always or immediately put my finger on it. My first experience with class D was pretty positive at first, but over time I came to realize that I wasn't as excited to sit down and listen to music or didn't listen as long.

I have heard this complaint about Class D amps before and it concerned me when I was making the final purchase decision on the W4S amp.

I did a quick scan of prices of the three amp brands you mentioned: Krell, Pass and M. Levinson and at anywhere near the output power of the W4S STI500 they are 3 to 15 times more expensive. This is really an unfair comparison.

Assuming quality audio reproduction of the equipment, Class D amps provide the following additional benefits:

They are very light,
Have very low power consumption, and
Give off little or no heat.

The pace at which the W4S is breaking in right now, my concerns about Class D lessen each day. I would possibly compare the "difference" in Class D amps with my previous Class A (up to 10 watts) /AB amp may be similar to how Magnepans sound different than other speakers. You either like it or not, but they do present the sound in a different manner. I don't hear any differences as big as Magnepans vs typical speakers in the W4S vs Class A or A/B amps, but possibly some slight differences.

Finally, the W4S STI500 does sound very very good with the Magnepans.