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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
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anotherbob
344 posts
 
So, at the mention of the brand Purifi in the beginning of this thread I thought for sure the poster would be discussing this...

”Specifically, HybridDigital Purifi Eigentakt amplification, a game-changing Class D technology (Eigentakt means “self-clocking” in German) that produces ultra-low distortion regardless of frequency or load.”

I’m admittedly very new to this hobby, but it seems like the poster purposely choose the lowest common (Purifi) denominator to speak about, as opposed to their newest and best.
ricevs
1,543 posts
 
Anotherbob is confused. The Purifi module has a nickname of Eigentakt. That is all. They are one in the same. Bruno’s last version of his amp circuit was called Ncore and is manufactured by Hypex. When he formed his own company he needed a new name for his latest version of his amp (so he used this German word for his new circuit).....therefore Purifi is the name of his company and Eigentakt is the nickname or name of the Purifi module that this thread is about. Most people, including myself, refer to the Purifi module as the "Purifi module" (no Eigens mentioned).....hence some peoples confusion.
https://purifi-audio.com/eigentakt/

I keep repeating that all Purifi based amps will sound different. It is not a magic bullet.....no one thing is. Just another class D circuit that sounds slightly better than the NC500 but can be tweaked to sound really fantastic.

There is a more powerful Purifi module under development.  After it comes out we will probably then be saying ET400 or ET700 or 1200 or whatever it is to differentiate between the two.  Right now there is just the one and only Purifi module (1ET400A......which stands for Eikentakt circuit with 400 watts/mono amp).

chepo
3 posts
 
Hi:
I am the top 3 in the list, ¡¡¡
Just retired general thoraxic surgeon,with 77 years old.And where are the other old people? Only alcohol,drugs,sex or ,,,
Thanks for all yours input and questions
ricevs
1,543 posts
 
I’m an old guy. And I have not had any alcohol, drugs or sex for awhile.....can I join?  Even top 10 would be fine.
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anotherbob
344 posts
 
ricevs: In further reading on this subject it appears that there is no “nickname” for the amp under discussion, it is THE name, as it is referred to that everywhere I’ve looked. You sir, are the one confused on this point. Why you conveniently left the actual name of the amp out is anyone’s guess.

In reading the test reports on this amp it is consistently rated very high, some calling it revolutionary or a game changer. Inaudible distortion and zero amp coloration of the sound, pretty much what most would consider a perfect amp to be. Clearly there’s more versions with higher power on the way.
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