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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
georgehifi's avatar
georgehifi
10,312 posts
 
He’s tried a few, and been on a disillusionment path with them, it’s expected to not feel confident with this one. I’m surprised he’s given them as much chance as this.

I know what Class-D would probably make you happy madavid0 OP, and that’s the Technics SE-R1 if you want to give that a go, hard to get one but possible.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 


There’s also a new approx $10K integrated Class-D from Technics called the SU-R1000 Integrated Amplifier around 22 kg
.
Said to have many of the GaN Class-D features of the far bigger SE-R1, but nowhere yet can find if it uses the 1.5mhZ switching frequency that "makes" the SE-R1.

Also it uses smp power supplies, even though it’s 22kg, Unlike the SE-R1 at some 60Kg because of it linear supplies.
No reviews or measurement tests as yet for this one from Technics


Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
I think this deserves a thread of it's own as it's more affordable than the SE-R1.

Cheers George
madavid0 OP
214 posts
 
I'll look around the local dealers to see if they have a SE-R1 for audition.

I really am giving class D a lot of chances. Maybe I really want to believe in the promise of high-quality audio in a small and cheap package. But I didn't go into this with my mind made up, I was successfully talked into trying it by you guys (and others). I really have to question though what are some of you guys' standards in audio. It's still burning in so we'll see. I hope this mid range mess sorts itself out.
soix
9,812 posts
 
Kudos to you @madavid0 for giving Class D a solid shot. Maybe send it to @ricevs to do some magic mods to it and then we can all enjoy watching Georgie sunshine blow a circuit.
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