Purifi Class D: Junk?


So, from the previous thread about high-end class D the Purifi module was brought up. I decided to get a cheap example from VTV, a simple stereo unit with a single Purifi module and matching Hypex SMPS. Standard input buffer. I got it in yesterday. First impression wasn't what I was expecting: weak, congested dynamics is what stood out to me. I expected greater expression through my ProAc D30Rs. The other problems such as poor soundstage, thin / boring character, etc, I marked up to needing burn-in before evaluating. So it's been 24 hours, I would still expect to get at least the high control / damping of high end class D and dynamic power, but it's just not present.

Could it be an impedance mismatch? Other manufacturers selling the Purifi with their custom input buffers are reporting 47k Ohms. VTV doesn't say in the manual or on the site. I checked the Purifi data sheet which reports...2.2k Ohms on SE???? That can't be right?? That's absurdly low! Am I reading the right spec? My preamp has an output impedance of 230 Ohms. Can someone confirm that the stock Purifi has this ultra-low input impedance?
madavid0
Talk about implicit bias!  Just read some of the other posts by the OP.
On top of which it's the most basic model from a company whose track record is worth checking out over on AudioScienceReview.
The outcome of this "trial" was about as predictable as that of a Salem witch trial.
GFi
opinion is essentially meaningless

And naturally his shill and name sake has to step in.
Once again on fuses for the gullible here that are thinking of throwing their money away paying $150+ for a 50cent fuse that’s just been dressed up to look glitzier.
You’ll never see the manufacturers of these (snake oil) fuses defending themselves or their products with the claims made on forums like these.

Just change the fuse if old fuse for a quality brand EE industry standard 50c fuse, as all fuses (even the snake oil ones) do age and still work but develop corrosion, sag and distort etc after too many turn on cycle surges.

Left to right
Quick blow fuse aging         and            slow blow fuse aging .
https://ibb.co/0ZtRv4J                          https://ibb.co/mbzs3RK

Cheers George
You are making people wrong by telling the world that they are gullible. Why would you put someone down for their EXPERIENCE? I may not agree with what everyone says but I practically never doubt what they say about what they hear. They could of had expectation bias or maybe had a cold that day but 95% of the time they actually heard what they say. I have done tons of A/Bs with multiple people in the room and NEVER did anyone hear something different. Back in the late 70s three humans, including me, A/Bed 10 brand new Supex cartridges......We all heard the differences and one of them was the best......The frequency response graphs that came with each cartridge showed no correlation to the sonics. I trust what George (and everyone) says about what he/they actually hears.....I do not trust what he/they says about things that he/they has not heard......why would anyone? Trust your experience.....trust others experience...do not trust opinions based on non experience. Please, love yourself and everyone. Allow everyone to have their own experience without putting them down.
It is a fact that the middle of the herd is not the top of the mountain or the peak of endeavor.

No matter how much the middle of the herd may look around and try to convince itself of that by looking at those (others) which may be similar and comfortable.

Hearing is one of those things that is not perfected in measurement or meaning, not by a long shot. Therefore we have no perfect correlation in measurement that can fit what we hear. Hearing is a thign that is a massive variable in quality and capacity tied to the brain, in discernment, a variance a great as the variances in human intelligence. And human intelligence can span a difference as large as a million to one, in cognitive speed differences. Seriously. that huge a range. (add 5 IQ points, halve the cognition rate or speed). Hearing is tied to this, and is similar. not the same, bit similar. connected to it. Thus hearing has a IQ connection or quotient of a sort. Not all ear/brains are the same. There is a range, of capacity, for discernment. differences between individuals.
To add, part of our hearing is self trained, self created.

So.....the map is not the territory. This point is ultra critical to understand.

But we can still have peaks and we can still have average. 

And it is noted that the average of what Class D is, has not yet taken over the peak of quality in the world of high performance audio. Specifically, it is not at the peak..for the ears that want that mountain peak of quality.

It may do so in the future and it may not. Who knows. The peak may move further away from where class D is headed. It’s a moving, living, breathing, growing, changing target.

I’ve torn down Class D amps and spent about 2 years of my life, off and on, trying to make it sound better. Via analyzing the electronic parts, their function and what they are doing wrong, and what changes are needed and then doing what I can.

To improve the correlation between what they do and the psycho-acoustic model of the ear, what that ear requires. And I made some great Class D amplifiers. So good that many folks thought the modded out versions that made it to an audio show, were among the best they’d ever heard. If not the best.

But they still did not compete with the best of the standard model of audio amplification, be it class A or class a/b, or tube based versions. They just don’t have it. I could get into the psycho-acoustic modelling and how that compares to what Class D is doing wrong, and how to deal with it re changes to the design of class D, and that would help people a lot. It would help designers and end users.

But that information is valuable, hard fought for... and it is my life blood in the world of putting food on my table ----and this is business.

Some day, Class-D, some day. Never Know. But.. not yet..not yet.