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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
madavid0 OP
214 posts
 
So, the question is, does this VTV really represent a baseline of what the latest class D can do? The LKV seems interesting but for that money you could get a used Mark Levinson 585, will this really compete? Also in that price range is the big Cherry amp with a beefy linear power supply. Frankly this price point seems way too high. If they can compete with good A or A/B designs at the same price point that would be one thing. But the Stratos is by no means a pinnacle amp, not even close. If the VTV can at least compete with the Stratos which I bought used for $800 shipped than I may switch over to VTV or something similar, perhaps get @ricevs to mod it, and then see where the upgrade road takes me from there.

The other factor is there can't be listening fatigue. That's something I can only judge with long-term listening. I don't care how impressive the sound is technically, if its fatiguing than it's TRASH even if it costs $1.50.
georgehifi's avatar
georgehifi
10,312 posts
 
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
One needs both listening/measuring, you need to back up what your hearing with measurement’s otherwise your just saying "trust me" I heard it which is subjective only.

To all buying/modding anything, there’s not one piece of half decent audio equipment that’s any good, that has not been designed using all the EE laws and test/measurement procedures, if it hasn’t I would give them a wide berth. Especially modders that don’t give any EE measurement/bench test proof on what they’ve done to back up their subjective mods, these guys are just "snake oilers" and usually fusers saying trust me.

Cheers George
soix
9,501 posts
 
To all buying/modding anything, there’s not one piece of half decent audio equipment that’s any good, that has not been designed using all the EE laws and test/measurement procedures
Really?  Not one?  Huh.  Guess they all must be perfectly designed then — and certainly no room for further improvement.  There are these pesky things called cost constraints though.  
these guys are just "snake oilers" and usually fusers saying trust me.
Well that’s just an over-generalized and ignorant statement.  Not everything that provides an improvement is necessarily measurable.  You don’t like guys who mod equipment.  Fine.  That doesn’t mean all or most of them are bad.  If they’re not good they fail, and if they’re good they do well like any other business.  The market is the final arbiter of whether a mod is “snake oil” or not.  Not you. 



georgehifi's avatar
georgehifi
10,312 posts
 
Really? Not one?
So you would purchase an audio product that was not designed using the Electronic Engineering laws and bench testing?? Good luck with that sunshine.

Or maybe you need to comprehend a little bit better
there’s not one piece of half decent audio equipment that’s any good, that has not been designed using all the EE laws and test/measurement procedures.


soix
9,501 posts
 
So you would purchase an audio product that was not designed using the Electronic Engineering laws and bench testing?? Good luck with that sunshine.
Maybe you need to comprehend better, sunshine. Just because something was designed using the laws of whatever doesn’t mean it was designed optimally or with the best parts. Hence, they can still be improved upon through modding, which was the whole point. It’s not all “snake oilers” as you assert.
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