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
I got the VTV with their buffer. I tried all of the op amps, (each requiring at least 36-50 hrs break-in with noticeable changes), and the Weiss, which is from their $25k Medeus DAC, absolutely blew everything out of the water. Pure transparency. Only then do you hear what the Purifi is capable of...completely on another level of musicality, sweetness, transparency. Completely smoked the Sparkos and Sonic Imagery.

Granted, I also upgraded all internal cabling to Furutech DSS and added their pure copper posts and inlets. Phenomenal once you get through a few hundred hours of burn in.. I played for a friend that has a whole setup of Tron amps (do the $ math) and $10k+ in power conditioning, with the same Furutech cables I have, and he was blown away. The Purifi module really does accomplish what Bruno set out to do, which is give you the best of tubes without the artifacts (that some like for hi-fi listening). I use this in my studio.

And yes, the amp out of the box sounded like complete garbage, worse than a portable bluetooth speaker. Needs real burn in to get there. And the buffer board exists for a reason..email Daniel Weiss for more info. ;)

@clustrocasual That's very interesting. If the Weiss is that good perhaps I'll hold off on returning it. How did you replace the cabling? Including the Molex connector cables?
I did not replace the Molex from the hypex power unit to the amp module, but its on my list. I would have to source the right cabling for this.

I did remove the Molex that connects to the IEC inlet and soldered the DPS directly to that board. I used the Furutech pure-copper connector clips for all other points, and soldered the interconnect from the XLR inlet to the board.

I plan to do a write up with pictures once I'm done with some final testing in a couple weeks. I did each part one at a time so I could hear differences, and with Furutech's notorious 300hr burn in, its taken me a few months. I don't change anything unless I hear a clear improvement. 

But the first thing I did was test the op-amps with basic OFC cabling and the Weiss really opened my eyes. (or is it the Purifi opened my eyes because the Weiss is transparent?).
If they are using the OEM Hypex boards as input boards it is crap. It is VTV’s fault.
???????  What are you talking about?  You can buy from VTV several different input boards......the Hypex OEM, the Purifi board, the custom VTV input board that allows all kinds of different op amps to be tried and also a custom VTV tube input board that also allows different op amps.