Purifi Class D: Junk?

Maybe I should have put "nickname" in quotes....I was just letting you know that the Purifi module and the Eigentakt module are one in the same. You notice the name of this thread.....does not say Eigentakt. No biggie.

What is important and that most don’t realize.....and I am repeating....is that the Purifi module is not perfect....it has a sound.....it does have a color....it does not have zero amp coloration.....nothing does. I modifiy the Purifi module and my mods allow much better sound.......I am not talking about a different input buffer, etc. I actually modify the module by changing the output coil, the caps to ground on the output and bypassing the main high voltage power supply with modified Wima caps. These mods do not change the circuit, nor any measurement worth noting. The Purifi module is not the Golden Goose, Golden Egg, silver bullet or whatever, just another step better than the NC500....the last Bruno circuit. There will be plenty of better circuits down the line....sorry guys....this is what is real. However, the Purifi module modded along with the whole amp modded will blow your mind. But next year, there will be something better.....as always. There is no "End Game" in audio......audio is infinite.

I communicated with the owner of VTV about what I've experienced so far and about the upgrade options. He said that he hasn't experienced what I have -- that tells me that his standards for audio quality may be lower than mine. He did mention that the tubed input board makes a big difference to sound stage and so can different opamp options. It seems that the various discrete opamps are more about coloration / tone, is that true? The worst problems I described at the start of this evaluation have mostly solved themselves with burn-in. Improved dynamics and soundstage won't make or break the sound, but the midrange is problematic. What do I mean by this?

Take a piano or a horn. Does it sound like an acoustic piano or could you mistake it for a synth? Does a horn sound like a believable, real horn? Would the better opamps fix this? Why does the standard Purifi opamp which is supposedly very low distortion fail to handle this? The Odyssey I'm comparing this to is by no means an especially high-end amp. It has a lot of current delivery and bandwidth, uses the good Symphonic Line parts, but otherwise appears to be pretty simple design. I busted the newer Stratos even further trying to fix it, now one channel doesn't work at all. The old Stratos I have is too inferior. I went and bought another used Odessey, a high-end Kismet that's only 3 years old. This should out-perform my Stratos and it'll be interesting to compare it with the VTV.

So how bad IS the standard Purifi in the VTV? Will the upgraded input board and discrete opamps move it to another level? Obviously the manufacturer won't say "yeah the base model sucks".

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.