OK, I've had the March Audio p252 in the system for two days.
I had a bit of a long strange trip comparing it to my old amp (Adcom 5802). When I first connected the March, I was sure I could hear a difference. A bit tighter in the bass, not as smooth in the highs. Was the image not as wide? The soloist seemed a little further back?
This evening I had a chance to A/B them, albeit under less than ideal conditions. Since I had to power them off before reconnecting, there was a bit of a lag between listens, and, of course, I'm getting up from the couch to do it. Just to complicate things, the March reverses the channels, so I had to be careful to connect right channel on my DAC to left channel on the March. I put in a pair of cables with bananas instead of spades, to make it easier. After trying to volume equalize on the music, I started doing it on a 1k test tone. As it happens, the two amps have the same gain, so once I started using the test tone, I realized I didn't have to change the volume at all. Eventually I got the switch down to less than 30 seconds.
The better I got at making the swap, the less I could hear a difference. When I started I was almost sure I could, to my distress. Ninety minutes later I'm pretty sure I would fail a blind test between the two.
On the one hand this is oh-so-predictable. I am pretty convinced, in my head, by the volume of tests that suggest this would be the case. On the other hand, on first blush I started hearing some of the things subjectivists and kilobuck amp designers like to say about Class D. I guess my doubts rule my biases even more than my reasoning!
All in all, it was a weird experience. I'd love to get switchboxes that would allow me to make more immediate comparisons. They'd have to be 1-in to 2-out, XLR and Speaker (with some pop protection?).
It's nice to have a cool amp here in the living room, so I can leave the A/C off and enjoy the music. Also, with only the DAC/Streamer and the little p252, I could get rid of the rack and de-clutter.
Next up, I'm thinking I'll test the Orchard Audio PecanPi against my Cambridge DAC. I'm sure the sound will be fine, but I really like the Cambridge streaming features, including Chromecast built-in.