bel canto and wyred 4 sound

The ASP module includes powersupply. So, they are pretty much plug /play.

The ASC module is meant to be powered from an ASP module OR from a stand-alone PS. At that point you can buy a transformer and a capacitor bank, or go SMPS.

The output sections are very similar...topology and device selection.

It would appear that W4S uses unmodified ASP modules with perhaps a few changes on the input end. My PSAudio, built in the same facility has what they call the 'GainCell' on the input. I have no detail on that, except it is a potted module.

Other 'd' implementations may have character of their own. Hypex, Spectron and the little known International Rectifier are all 'd' entries. Spectron is proprietary, Channel Islands uses Hypex and I have no idea about IR modules, except I've got one out in the garage needing a power supply.

The 2 major topologies of 'd' amps, what are called 'FullBridge' and 'HalfBridge' may account for differences in sound.

Magfan, aside from adding an input buffer, I know for a fact W4S does modify their modules.

Would you or anyone consider such changes making the ASP moduled amps an Apples / Oranges proposition or maybe like a Fuji /Gala? (I'm a BIG fan of Apples!)

Changing (upgrade?) some caps? The only thing that would have a major effect, IMO, would be to change the feedback loop gain. I doubt even changing parts in the Zobel would have a major effect. The W4S integrated also has a different input impedance than the 'stock' ASP module OR my PSAudio which is a near-dead ringer. That supports your 'input buffer' remark.

I'd love to know what changes W4S makes. IF they are THAT major, why aren't they trumpeting it to the sky?

I'd LOVE it if someone organized a 'd' amp shootout. If it were local enough, I'd even bring my GCC250 over and put that in the rotation.

Fuji/Gala... :D

Yes, caps are changed in a couple of locations.

I'd love to be present for a Class D comparison too. Off the top of my head, the only others I've heard were Bel Canto's TOTL monos. They sounded good too, but were in a different rig/room so not really much of a comparison.

Wyred 4 sound amps are well worth the current asking price, they are very good sounding amps, but not great. My experience with the ST-250 impressed me to some degree and felt a need to play the highest quality recordings (audiophile music) to make it sound good, whereas other recordings didn't quite measure up. I am from the camp that a digital switching amp could benefit from an analog power supply but I have to give Cullen Circuits a thumbs up for implimenting a switching power supply that is acceptable. After inserting the older PS Audio HCA-2 the overall musicality regardless of the quality of the recording improved quite substantially. One would think that as time goes on that the sound quality of digital switching amps would improve but it is apparent that this is not the case here. The HCA-2 with its panoramic sound and analog power supply fleshes out velvety highs, bumped up midrange coupled with its ability to layer and texture the music in such a delicious way is superior in most all areas and found the overall involvement in the music was stepped up quite a bit. This is my opinion and I could still recommend the wyred 4 sound amps at their current going prices but I don't classify them as high-end but just very good midfi.