Purifi Class D

On 1/11/2021 at 9:19 PM, GUTB said:

Those of you who think you like your class D, I recommend being honest with yourself. Do you REALLY enjoy listening to you music? When was the last time you turned on your class D and got sucked in? Has it ever happened? Is your system spending more and more time left alone and you tell yourself it needs this or that upgrade? Once again I'm forced to accept that class D has serious killer problems and I doubt it's a phenomena I'm alone in experiencing. I don't think it's matter of discernment or having experience with high-end audio.

I don't like my class D, I love it.  Yes, I enjoy listening -- about 6 hours a day.   The sound is, to a great extent, like a live performance.   Class D can have the intimacy, immediacy, weight, richness (for lack of a better word) and dimensionality of tubes.  No familiarity with the model you tried, so have no opinion about that particular model, but Bruno has cracked the code on class D.  And the Mola Mola amps aren't fussy, which I like.  You can just plug them into the wall and they sound great, consistently.

Not here to plug my amps or argue, just to say that an overarching statement like "class D sucks and so do you if you can't hear it" isn't valid.  Anyone exploring amps should give class D a try.  Don't fall for the myth that topology is destiny.  

3 hours ago, John Hughes said:

So, I thought I'd chime in to this discussion.  Been in the audiophile industry in the digital realm.  Been a stone cold analog fanatic. Lived with at least 6 different digital or SMPS amp designs as well as many of the classic Solid State including Levinson, Spectral, First Watt (J2 being my last amp).  Several of the most extreme tube systems including Audio Note, and for a period of fortunate time an entire analog Shindo tube setup including turntable. Have 'showed' with many other amp designs at RMAF, CES etc.   I've been out of audio for a while, but have been getting re-acquainted with it.  After a lot of research I got the VTV Purifi amp with the Sparkos input buffer. I'm running a Holo May Dac into it and I have a pair of speakers of my own design: 15" open baffle, single driver speakers with a Raven super-tweeter (100db efficient).  

 

I will say upfront that a system is a sum total of all its components, and put a component into it that is not sympatico won't work.  If you have worked hard to get the best tube sound and you plunk a digital amp into the mix, you are probably not going to be wowed.  For me, I am supremely happy with the VTV, with Sparkos.  But it was actually my discussions with VTV that prompted him push for the design of the tube input buffer, though I haven't tried it myself yet.  

 

You might think that using a 400 watt amp with 100db efficient speakers is a mistake, but that amp has to control a 15" open air driver.  And at least for me, the match has been exquisite.  The noise level with Purifi is vanishing low on this highly efficient system, I don't think a tube amp could match it!  The VTV punches way above its price level with the right care and attention.

 

I get more spine tingling realism, more subtlety, realistic dynamics, clear and smooth treble, bass in the upper 20's, transparency and lack of coloration.  The best system by far, I've assembled. Overall better than tubes, easily better than A/B solid state.

 

I just wanted to counter the experience that Gutb has posted here, as some others have done.  I do have the benefit of almost 30 years experience designing and installing systems. And I have an army of ancillary products, cables, tweaks and voodoo to get what I want out of a system :)  But a good digital amp today (I wouldn't have said this 10 year ago) IMHO is as good as other amplification in the context of intelligent system design.  

 

All that said, I will say that I am super interested in the Orchard Audio GaN amps!  And I'll love the hear the Mola Mola products too sometime. 

I haven't had the chance to test a class D amp with a high-end all analog front end (source and source material). Have you done this, any conclusions? Thanks! 

41 minutes ago, Rexp said:

I haven't had the chance to test a class D amp with a high-end all analog front end (source and source material). Have you done this, any conclusions? Thanks! 

Not with this current generation.

The audiophonic Purifi model has 3 gain settings on its interface card: https://www.audiophonics.fr/en/blog-diy-audio/36-set-gain-bypass-on-purifi-amplifier-module-ampli.html

If you can live with only 12db gain from the amplifier, would it not make sense to use the "bypass" mode which avoids the use of opamps entirely ?

8 hours ago, hopkins said:

The audiophonic Purifi model has 3 gain settings on its interface card: https://www.audiophonics.fr/en/blog-diy-audio/36-set-gain-bypass-on-purifi-amplifier-module-ampli.html

If you can live with only 12db gain from the amplifier, would it not make sense to use the "bypass" mode which avoids the use of opamps entirely ?

This can be problematic sometimes, the only thing one can do is try it and listen.  Sometimes the sound will lack "body" and "force" without the active input gain stage, and this will depend on the output impedance/current capability of the driving component.

On 2/2/2021 at 3:14 PM, Matias said:

I am just waiting for Bruno to finish his new more powerful Purifi modules.

A few months back, contacted Purifi and they stated that they had no immediate plans for a release of more powerful modules.

Has that changed?

25 minutes ago, 57gold said:

 

A few months back, contacted Purifi and they stated that they had no immediate plans for a release of more powerful modules.

 

Has that changed?

Audioxpress magazine had an article about a factory visit where they said that. Lard Risbo interview with Erin on YouTube he says Bruno is working with high power. That's it.

A less than glowing review of the NAD implementation:

http://www.10audio.com/nad_c298.htm

On 1/12/2021 at 5:19 AM, GUTB said:

Those of you who think you like your class D, I recommend being honest with yourself. Do you REALLY enjoy listening to you music? When was the last time you turned on your class D and got sucked in? Has it ever happened?

I do enjoy listening to my music. the last time I turned on my Purifi/Neurochrome amp was today and I was sucked in. it happens all the time. You are indistinguishable from a troll.

On 3/26/2021 at 3:20 PM, Rexp said:

A less than glowing review of the NAD implementation:

http://www.10audio.com/nad_c298.htm

 

From a guy that believes in audiophile fuses. That review has absolutely zero credibility.

On 3/10/2021 at 5:32 PM, jaytor said:

I tried bypassing the input buffer, and even though I have a low 66ohm differential output impedance from my preamp, I thought the sound was more dynamic with more weight with the input buffer active. However, I do have long balanced interconnects (~8M). So your results may be different. You won't hurt anything by trying it. 

My experience as well. Even with a unity gain buffer the sound had more weight, was more precise, and it was more dynamic. Of course, if my DAC had an output impedance of 10Ohm I would probably have felt the same with the buffer bypassed, but as it stands my Topping D90 has an output impedance of (I think) 300Ohm on XLR. Maybe the Neurochrome buffer eats some detail – of course any additional circuitry does – but this one definitely eats inaudible stuff, look at the measurements, they are insane. The final result is absolutely stunning and with my new (DIY) speakers I have sound clearly outmatching that of any system I have heard at any audio fair, except for: a full FM Acoustics system (costs: like a small house in Munich), Von Schweikert Ultra 11 driven by some huge VTL amps, and Wolf Von Langa Son speakers driven by Air Tight (3211 power amp) electronics – and enjoyable like the sound coming from Harbeth 40s (forgot which amp). So I cannot complain. 10K EUR in raw components, try to imagine how much it would cost if produced by a boutique hiend manufacturer...

I listen to my system about eight hours a day since I've been working at home for the past year and my desk/computer are at the back end of my listening room. I've been quite pleased with my Purifi based amps. I also have a number of class A and A/B amps that I've compared them to including a couple older amps (Krell KAV-250a, Bryston 4B-ST), a Parasound JC5,  DIY FirstWatt F5 turbo monoblocks, and Neurochrome Mod-286 monoblocks. The Purifi amps compare favorably to all these. 

For the last couple weeks, I've been listening to the Purifi amps with VTV buffers that utilize a 6922 dual-triode feeding a pair of Weiss discrete op-amps. At first, I was disappointed with the sound compared to the Neurochrome buffers, but I'm starting to enjoy the sound. I'm not sure if I'm just getting used to them, or if they are still breaking in. I have around 100 hours on them now. Unfortunately, it's a pain to switch back and forth since they use different connectors. After I put another 100 or so hours on them, I may switch back to give the Neurochrome buffers another try. 

Unless the VTV buffers continue to improve a fair amount more, I'd have to say that the Neurochrome buffers are a much better value. But I'm also considering trying a different set of tubes to see how much difference that makes. 

13 minutes ago, jaytor said:

I listen to my system about eight hours a day since I've been working at home for the past year and my desk/computer are at the back end of my listening room. I've been quite pleased with my Purifi based amps. I also have a number of class A and A/B amps that I've compared them to including a couple older amps (Krell KAV-250a, Bryston 4B-ST), a Parasound JC5,  DIY FirstWatt F5 turbo monoblocks, and Neurochrome Mod-286 monoblocks. The Purifi amps compare favorably to all these. 

 

For the last couple weeks, I've been listening to the Purifi amps with VTV buffers that utilize a 6922 dual-triode feeding a pair of Weiss discrete op-amps. At first, I was disappointed with the sound compared to the Neurochrome buffers, but I'm starting to enjoy the sound. I'm not sure if I'm just getting used to them, or if they are still breaking in. I have around 100 hours on them now. Unfortunately, it's a pain to switch back and forth since they use different connectors. After I put another 100 or so hours on them, I may switch back to give the Neurochrome buffers another try. 

 

Unless the VTV buffers continue to improve a fair amount more, I'd have to say that the Neurochrome buffers are a much better value. But I'm also considering trying a different set of tubes to see how much difference that makes. 

Well tubes can make a huge difference, but I do trust VTV to have selected some that match well (he's been in the tube business for decades).

16 minutes ago, John Hughes said:

Well tubes can make a huge difference, but I do trust VTV to have selected some that match well (he's been in the tube business for decades).

Yes, I suspect you are right. It comes with Genalex Gold Lion tubes which seem to be fairly well regarded for a new production tube. 

2 hours ago, mocenigo said:

 

From a guy that believes in audiophile fuses. That review has absolutely zero credibility.

Have you tried an audiophile fuse? I haven't but always stay open minded. 

http://www.10audio.com/evs-vtv.htm

On 3/29/2021 at 10:57 PM, mocenigo said:

From a guy that believes in audiophile fuses. That review has absolutely zero credibility.

You can read about snake oil fuses here. It seems to work for some. 

2 hours ago, R1200CL said:

You can read about snake oil fuses here. It seems to work for some. 

I can understand that moving from a crappy fuse to a well engineered one may make sense. After all it is just a wire in a little glass tube, and engineering that well should not be an overtly complicated matter.

But then I read that some fuses have "silver salts" inside, that have been "tuned" according to "quantum resonance" and that apparently they also have gold, plutonium, unobtanium, and whatever. Then I know they are in the realm of pure fraud.

1 hour ago, mocenigo said:

 

I can understand that moving from a crappy fuse to a well engineered one may make sense. After all it is just a wire in a little glass tube, and engineering that well should not be an overtly complicated matter.

 

But then I read that some fuses have "silver salts" inside, that have been "tuned" according to "quantum resonance" and that apparently they also have gold, plutonium, unobtanium, and whatever. Then I know they are in the realm of pure fraud.

All of the the power going to one's component passes through the very small AC line fuse.  Considering this, it is not hard to believe that the fuse it self will influence the final sound of the component;  when things like power cables and transformers used make significant differences in sonics.  I would suggest you audition a Synergistic Research Orange fuse as an AC line fuse in one of your components, they are returnable for a full refund, to at least have some experience with fuses, allow it 100 hours of break in, and then listen compared to a stock OE fuse.  See what you think, you might be surprised.  I know the results with aftermarket fuses have consistently surprised me, when my expectation was to hear no difference.

My Purifi amp build uses an Orange fuse for the linear supply feeding the input stage, the fuse for the SMPS 1200 feeding the modules is soldered in, so I have yet bothered to change it, but I will get around to that someday.

My experience is that incoming AC power responds to "treatments" (various power conditioning approaches) quite notably, and in fashions which seem to defy normal engineering concepts.  I suspect that that all of these results can be properly explained technically, but I certainly get that because they are not explained technically (purveyors of AC line treatments, including fuses, often appear to use obfuscating concepts in their marketing explanations, apparently in an effort to protect their actual tech) many believe them to be "snake oil".

The NAD C298 amp has the Eigentakt which was developed by Purfi which made its debut in the M33 integrated amplifier. It is suppose to provide a better class D power supply concept which includes reducing THD to a very low percentage. I am interested in this amp myself. All the reviews have been very good and though it has more of a neutral sound, it is suppose to be very balanced with the highs mids and lows. The high's are suppose to be smooth and not clinical. The price is also pretty good as well

1 hour ago, barrows said:

My experience is that incoming AC power responds to "treatments" (various power conditioning approaches) quite notably, and in fashions which seem to defy normal engineering concepts.

Hi Barrows. Nice post. 
I would like to think a properly designed power supply ought to be immune to fuse changes. 
Any thoughts ?

You may post answer in the fuse tread I made. 

18 minutes ago, R1200CL said:

Hi Barrows. Nice post. 
I would like to think a properly designed power supply ought to be immune to fuse changes. 
Any thoughts ?

You may post answer in the fuse tread I made. 

No link for the fuse thread?  Anyway, a quick answer, then back to the Purifi stuff!

My experience suggests that the better the power supply is, the less it may respond to upstream changes (power cables, power conditioners, fuses, etc).  But, all of these things still seem to matter some, it is just that with really really good power supply design they make less of a difference.  I find the same deltas in difference to apply to things like USB cables: they make less of a difference when the USB source and USB receiving designs are very, very good, but they still make some difference.

13 minutes ago, barrows said:

No link for the fuse thread?

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