Purifi Class D: Junk?

Another interesting finding. I decided to swap out my reference power delivery to the amp: LessLoss level 1 power filtering cable + Firewall 64x from a Furutech GTX-D(r) NCF outlet to a standard black 14-guage power chord from a standard outlet. The difference on one test track was...almost nothing. Maybe the it was a touch muted / muffled on the standard cable, but nothing you couldn't chalk up to audio memory effects. This hasn't been my experience with my linear amps. I wonder if the switching power supply is just agnostic to mains quality -- or it's already so messed up the mains quality won't make a difference?

Okay...I'm done with this amp. I tried listening to King Crimson's Larks' Tongues in Aspic, and right on the first track the part with the rattler/shaker percussion thing...it doesn't sound like an actual instrument but like a diffuse low-resolution jumble of tones, like the percussions were blurred beyond recognition. It's been plenty burned in at this point. Earlier I had emailed VTV asking about this poor midrange performance and the response basically said he hasn't experienced that problem.

I mean...look. If you don't think THAT'S a problem, if THAT sounds fine to you, then I have no business considering this amp any further...right? If it was "oh yes this or that option improves things" than okay maybe it would be still worth considering. New opamps aren't going to fix it, there's no reason to believe they will. Besides this...the almost complete lack of engagement and boredom with the sound isn't going away. It's not about harmonics, I think the Purifi does a "good" job with returning the normal even order harmonic information you'd expect to hear. Is it the trashy midrange which is doing this and my mind is simply rejecting it? Class D distortion? 

I'm told that this isn't a real trial because...I'm not using the little custom input board with discrete opamp? Really? Will that REALLY have such a major impact on the sound to transform it from awful to good? Why would Purifi release a bad-sounding input stage? Are they deaf? I think I've given it an ample chance. Any disagreement?

So how bad IS the standard Purifi in the VTV? Will the upgraded input board and discrete opamps move it to another level?

In my experience, yes upgrading the input board changed the VTV Purifi amp from unacceptable to acceptable. Others have reported a similar experience:  https://www.audioasylum.com/cgi/t.mpl?f=amp&m=238411

My thought is the following. At $979, the VTV Purifi with Hypex buffers is by far the lowest price Purifi stereo amp on the market. Everybody else is selling Purifi stereo amps in the range of $1400 and above, and only with custom buffers. Presumably nobody else wants to offer the Hypex buffer because it is a poor match for Purifi. If you upgrade the VTV with custom buffers, then the price jumps up to $1400 and more, making it similar to the rest of the market. So the $979 price is only there to attract attention and bargain hunters, even if the Hypex board doesn't work well with Purifi.

It's a little surprising that Purifi would release a compromised product to the public to represent their brand. I guess I'll look into a input upgrade then. It's just there's no way anyone with any kind of good amp experience would think this is fine, forget about great.

To be fair, Purifi does not sell their module with this input buffer. In fact, they don't sell their products to the public at all except to the DIY community. The amp you bought includes a buffer that wasn't even designed with the Purifi module in mind. 

Purifi expects that their OEM customers will add value to their module by designing proprietary power supplies, input buffers, and other logic and circuitry. The NAD M33 or the LKV Veros are more the kind of products they envision, or at least the VTV with their tube input buffer.

Amplifiers built with the Purifi module are only going to be as good as the sum of its parts, like any other electronic product. If you build the amp with an entry-level power supply and the cheapest possible input buffer, it's not going to be an good indicator of what the module is capable of.