Purifi Class D: Junk?

Seems unlikely that this would be the case in both channels (assuming that's the case). Since this is a stereo amp, perhaps an issue with the power supply?

I agree. I don't know how the Purifi module works, but if its anything like ours there is a low voltage side of the module where the comparitor and triangle wave processor reside. If the power supply has a regulator for all that, it could be that something with it is amiss- for example, the regulator is oscillating. At any rate it seems a good idea to get it checked out.

If @madavid0  is using the VTV buffer boards with Weiss opamps, these have Sparkos discrete regulators for the low voltage power, and these are independent for each channel. 

It's possible, though, that the SMPS supply is configured for regulated Vaux output which could certainly cause problems. 

I’m listening to a Chinese made bought on eBay Icepower amp for $150. Sounds perfectly acceptable with a tube preamp, which is a Bellari PA555. Total investment of $425.  The amp sounded not very good until it had run a day or so.  

I don’t think there’s anything wrong with the amp unless he messed it up popping opamps in and out. Try a blind listening test and get back with the results.

I spent some time today switching between my Purifi amps (using Neurochrome input buffer), Neurochrome Mod-286 amps, and Parasound JC5.

First, I should say that my ears aren't as discriminating as they used to be. I've suffered with Tinitus for many years, and my high-frequency hearing is not what it used to be. So take these observations with that in mind.

I used the same interconnects for all three amps, but I had to use longer speaker cables with the JC-5 since it's a stereo amp. The cables were exactly the same construction, just 2.5 meters instead of 1 meter. Also, I used a different (although similar) power cord with the JC-5 since I needed a longer one.

I set the levels using a pink noise -10db recording with a sound pressure meter with C weighting measuring 64db. For most of the recordings I listened to, this would be about my average listening level. A couple of the recordings were a bit lower volume than I'd normally listen.

The songs I listened to were Sophie Zelmani - Why, Jennifer Warnes - Way Down Deep, Shirley Horn - Beautiful Love, Dominique Fils-Aime - Birds, Ray LaMontagne - This Love Is Over.

I turned off my subwoofers for these comparisons since they have their own amps and I didn't want their contribution to influence my impressions. My main speakers (GR Research NX-Oticas) don't play very low without the subs, so I can't really assess the deep bass performance of the amps.

All three amps have a fairly similar presentation, although the JC-5 was slightly more laid back than the other two. The overall differences between the amps were not real obvious.

The JC-5 is slightly warmer sounding with excellent dynamics and smooth midrange. The highs (to the extent I can still hear them) sound clean and natural. Compared to the other amps, the biggest short-coming is a somewhat narrower sound stage. I suspect this is because the other amps are monoblocks.

The Modulus-286 amps were the weakest of the three. They still sounded quite good, but had a bit of honkiness (if that's the correct term) to the upper bass and some unpleasant sibilance on female vocals. At higher volume levels, I've noticed these amps get a bit more congested sounding, probably due to their more limited power, but at the volume that I was playing today, they sounded fine.

The Purifi amps were just a tiny bit rougher sounding in the upper midrange compared to the JC-5, but overall cleaner than the Modulus-286. They also had a touch more energy in the bass compared to the other two amps, most obvious on the Jennifer Warnes song.

At this point, I'd be perfectly happy with either the JC-5 or the Purifi monoblocks, but I'm hoping I can take the Purifi amps to the next level with the new input buffers I just got. I'm waiting on a couple of connectors before I can install them (hopefully next weekend). The Purifi amps are also a lot more efficient which is particularly nice during warmer months.