2. amps-preamps
  3. 162284-76532

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
jaytor's avatar
jaytor
765 posts
 
I think it is perfectly reasonable to report that you weren't happy with the particular VTV model you have, but to lump all products that use the Purifi module in the same bucket is pretty rediculous. I haven't personally heard any products that use the Purifi module yet, but I know from my limited experience listening to products that use other class D modules that there is a lot of differences in the way these amps sound depending on how they are designed and built. 
mr_m
1,900 posts
 
jaytor,
Same can be said for Hypex modules. Many designers incorporate them in many different ways with excellent results.
mike_in_nc
1,153 posts
 
I have listened quite carefully to a pair of monoblocks made by Apollon Audio using the PuriFi modules. In my system, in my room, with my own source material, I consider them in the same league as the well-respected Class AB amp I normally use -- I might wind up liking them better. As a frame of reference, the AB amp has an MSRP more than twice what I paid for the monoblocks, delivered. (I don’t intend a value comparison -- there are reasons for the cost differential, at least some of which involve value added, such as dealer support, longer warranty, and so on. Just to say it’s not a low-cost item.)
Oh -- I don't think either the AB or the PuriFi amps are "junk."
madavid0 OP
214 posts
 
Well, I installed the VTV input boards and Sparkos opamps today. I won’t post immediate findings because those are always defunct within a day or two so I’ll let it burn in for the time being.
clustrocasual
101 posts
 
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. ;)

More to discover