Purifi Class D

[mocenigo]

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.

[mocenigo]

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.

[mocenigo]

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...

[mocenigo]

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.

[mocenigo]

5 hours ago, fas42 said:

"Sound dramatically better" is just another way of saying that distortion artifacts are far less obvious - but the D word, Distortion, is deeply frowned upon by audiophiles - after all, measurements have 'proven' for decades that digital playback is devoid of the deadly D, 🤣 🤩 🤣.

No. Some recordings have never been transferred properly to digital. They sound great on the old LPs printed from the analog masters, but the transfers are crap. There are, sadly, a few. It may be because the remastering technician could only work on copies of copies of the original master, or because the master tape deteriorated, who knows. But there are specific recordings where the vinyl discs are superior to all digital copies made so far, and when the last vinyl disc will have deteriorated as well, good sounding copies of that particular recording will exist no more.

 

Solti’s ring almost met that fate.

 

Harry Belafonte’s Carnegie Hall concert apparently met it (I trust here a friend that could compare several transfers, Corona restrictions prevented me from being there.)

[mocenigo]

9 hours ago, Iving said:

This apart from the argument that you can build a musically satisfying analogue playback system on a budget - whereas making digits musically inoffensive demands money, blood, sweat and tears.

 

Oh please no. It is not difficult to make "digits" sound not just inoffensive, but spectacular.

[mocenigo]

8 hours ago, fas42 said:

All one has to do is make a high quality capture of that 'brilliant' vinyl disc - these days that's not so hard, and then it's available, "forever" ... unless you believe that magic is imparted at the actual moment of the vinyl tracing the groove, in some mysterious way 🙂; and is lost when you merely reproduce a needledrop ...

 

Well, you know, there are a few around, supposedly high quality captures of that vinyl disc. They are crappy.

[mocenigo]

6 hours ago, fas42 said:

 

"Supposedly high quality captures" equals "crappy" ?? There's something a little bit wrong here ... hmmm, what do you think it could be? 🙂

Well, the guys that did the transfers list their equipment. Great turntable, pickup, arm, ADC, cleanup software… but it sounds bad: noisy, without treble, no dynamics…

[mocenigo]

14 minutes ago, fas42 said:

The recording ... ?

Not sure. Maybe the record. In the Harry Belafonte Carnegie Hall Concert case a friend has a very good sounding record. So maybe the folks that did the transfer had a worse record, either the pressing or it was badly worn out.

[mocenigo]

1 hour ago, Mike48 said:

More power, otherwise similar specs. Does that sum it up?

yes

[mocenigo]

19 minutes ago, Allan F said:

FWIW, the following is an excerpt from AF Digitale's review of the Rouge Audio Studio N8 stereo amplifier based on the new Purifi 1ET7040SA module:

 

Compared to the 1ET400A, this Purifi 1ET7040SA marks a big step forward, in addition to greater power, the sound seems to have acquired a soul: now it is richer and more harmonious.

AF Digitale usually writes just loads of cr*p, and this is no exception. If you look at their descriptions of digital technology, for instance, you will see a total lack of understanding of science and engineering.

 

The Purifi designers claim that the two modules will sound indistinguishable except if you need more power at low impedance; and that you will only hear a difference in that case.

[mocenigo]

5 hours ago, Allan F said:

 

For the general reasons stated by @barrowsin his earlier reply to my question regarding sound quality and the two modules, improved sound quality with the 1ETt7040SA may be an unintended and fortuitous benefit in certain systems.

Yes, but only when the impedance is really tough and/or you need a lot of power in the low frequencies. Which should almost never be the case, but some audiophiles still buy speakers needlessly difficult to drive…

 

The 1ET7040SA exists to satisfy the needs of users that otherwise would have to purchase one of those d’Agostino/Griphon/etc monsters that can pull out 1Kw at 2ohms and lower. And provide a differentiator between the DIY and OEM options.

 

And there is NOTHING unintended and fortuitous in the sonic benefits it may have in some circumstances. the ridiculous statement comes from the same place that causes audiophiles to believe that “an artistic approach” or “high quality capacitors and resistances” may make a difference, I.e. faith in snake oil, whereas audio reproduction is science and engineering and nothing else.
It the two modules are used with speakers they are meant to be driving comfortably, there will be no sound difference. If one uses speakers that the 1et7040sa will drive in its ideal operating conditions and the 1et400a will not, there will be a difference.

 

The folks at AF Digital, with their incompetence, are either victims of self-delusion, or price tag, or have exactly that type of speakers.

[mocenigo]

2 hours ago, barrows said:

Umm, dude  you are wrong if you think all capacitors and resistors are the same.  Noise and distortion of different capacitors and resistors are both measurable and audible.  While I agree that there are some audiophile "beliefs" which are not based in reality, quality and performance differences between passive parts such as these are not debatable.  Perhaps how large those differences are could be debatable...

 

I actually agree with you but for me manufacturing decent capacitors should be standard, yet there are several cheap ones which are just crap. So there would be "quality" and "crap" – not "high quality". For instance, not only what you say is correct, but capacitors may suffer from magnetostriction, pick up vibrations, have a filtering effect that differs from the ideal model in a significant way (creating the "bright" or "dark" capacitors, which is also of course nonsense since the effect would be the opposite if they are in series or in parallel with the signal...).  When they start speaking of "high quality" of these components I get immediately allergic. For me it is absolutely normal to buy well build ones, such as clarity cap. The differences with the "higher quality' ones is mostly in the shape of the deviations from the ideal model and I sincerely doubt that there are ideal capacitors. Another differentiator is longevity and stability, esp in a hot environment.

 

Similarly, I buy good Mundorf inductors because their foil-like windings and if there is a core, the quite one core, guarantee a working closed to the ideal one than many other products - so the simulations of, say, a crossover, with actual driver measurements included, will be closed to the real thing than with a smaller inductor, with a higher resistance, with less controlled flux.

 

But if somebody is trying to tell me that having silver or gold foil in a capacitor or inductor will make it "better", well, maybe different, and it would be fun to try an ABX test to see whether they can distinguish them...

 

 

2 hours ago, barrows said:

Just a single example: all resistors add noise to the circuit path they are used in, some resistors add less noise than others.  This noise adds up, considering how many resistors are in many audio circuits, and given contemporary low noise circuit designs resistor noise is a significant part of the noise at the output of components.  Susumu makes some of the very best low noise thin film resistors available, and their company touts the low noise characteristics of their resistors-they do not do this for "audiophile" reasons, as that market is tiny, they do so for industrial use applications, such high precision measurement and med-tech uses.  There is nothing crazy about this, some resistors are better than others.

 

True, some resistors have also a non-negligible inductance. That's why I buy good MOX resistors, and not wirewound. 

 

Maybe we are so negatively spoiled by crappy and cheap components that what I consider decent engineering, a normal prerequisite, is now a luxury.

 

 

[mocenigo]

34 minutes ago, Allan F said:

 

I don't know if you don't know the meaning of unintended or fortuitous, but your statement doesn't make any sense in the context of this discussion.

 

I see you have edited it. So let us see from the dictionary

 

unintended | ˌʌnɪnˈtɛndɪd | adjective Not planned or meant: the unintended consequences of people's actions.

fortuitous | fɔːˈtjuːɪtəs | adjective happening by chance rather than intention: the similarity between the paintings may not be simply fortuitous. • happening by a lucky chance; fortunate: the ball went into the goal by a fortuitous ricochet.

 

I can confirm that I intended to use these works exactly as they are defined in the dictionary.

Also, the statement makes sense.

 

And, yes, I see that you were mistaken by inferring that I claimed that resistors and capacitors make no difference. Ouch ouch ouch! :-)

 

 

[mocenigo]

23 minutes ago, barrows said:

This could be the case.  A huge part of the training of engineers is that they are always trained to deliver a design which will "work" at the lowest possible cost.  While given design may "work", this approach might not be the best when sound quality is a design goal.  For example, the sound quality of a resistor used in a control circuit for a washing machine is of no consequence, and cost is likely the most important factor besides longevity/reliability.

In my work in audio, when hiring engineers for design help, it has often been hard to get those engineers to understand that cost may not be so important, and that it is OK to spec a resistor which might be 2x or even 4x the cost of a lessor part.

 

Most of engineering today is "do as cheaply as possible and it is explodes, let it explode after the warranty has expired".

[mocenigo]

42 minutes ago, barrows said:

Thanks @Judfor pointing this out, I had not listened to this interview.  I happened to have a pair of OPA 1656 left over from a  previous project, and just swapped out the 1612s on my Purifi build with the 1656s (on the Purifi EVAL 1)...  Warming up in the system now...  the 1656 has 2x the current of the 1612, and I always suspected that the current delivery of the 1612 was a bit on the low side for this purpose.  Very cold amp right now, but sounds a bit better with the 1656s...  I'll let it run overnight to warm up and listen more tomorrow.

 

Ah, I use Neurochrome's Universal Buffer. No shortage of current with that one.

[mocenigo]

4 hours ago, Allan F said:

 

Congratulations. But your statement still doesn't make any sense. 🙂

Over and out.

 

It does. A lot of audiophiles drink the cool aid of snake oil vendors that speak of "hand made cables", "after many experiments with different types of conducting material and dielectric, all validated with listening sessions" and so on, as if things in audio happened "just" because untrained people try out many combinations. And they believe they can be as good because they try a lot of stuff.  Whereas, even if many here poke fun of audio "science" review, and a few guys there even deserve that, well, audio reproduction IS science and engineering, and nothing else. Building better and better slings for marbles as a hobby does not make one an experimental physicist at a synchrotron, but in the audiophile world this seems to be the common belief.

[mocenigo]

3 hours ago, Allan F said:

 

 

 A rather significant difference in the description of the performance improvement of the NCOREx compared to the original NCORE. And I very sincerely doubt that the difference can be attributed to semantics, i.e. that, technically, one could argue that an increase of not less than 10 times is at least 2x better. 🙂

it may also be that in one case they measured the power of the residual noise (which is measured in V but assume constant I…) and the corresponding subjective intensity change. Then 10=2.

 

 Roberto 

[mocenigo]

3 hours ago, 57gold said:

Be interested in your listening tests.  

 

Though, DYI is NCD (no can do) for me.  I burn myself every time I try to use a soldering iron.

Well, these amps sound incredibly neutral and especially the Purifi ones have very smooth treble, with an absence of grain that I heard before only with small power DHTs.

 

They are also the most silent and clean amps I have ever heard, even with very sensitive speakers. Details and dynamics are just right.

 

They are also brutal - no defect in a recording will be masked, which I consider a good thing. 

[mocenigo]

15 hours ago, PYP said:

They also reveal whatever feeds them.  Reducing the noise in the components that are upstream is worthwhile, as is reducing the noise from the electrical system.   

 

My approach is mixed objectivist/subjectivist in the following sense: the sound is fundamentally characterised by the speakers and the listening environment – and these two are so fundamentally imperfect, that, within the best we can afford to purchase or build ourselves, we have to pick by necessity what we like most.  But electronics are a solved problem, so by picking them intentionally components that reproduce the signal as perfectly as today's technology can do (which is achievable at modest expenses, and after that there are differences that are either deviations from fidelity or indistinguishable – of course provided that the measurement set is complete as of today's tech, not according to the marketing of the 80s) I remove them from the equation, provided of course that electric matching is appropriate. At this point, to finish setting up the system I only have to play with the speakers and the room.

(As for the electronics: even TAS, when they listened to the Topping D90SE, had to admit https://www.theabsolutesound.com/articles/topping-d90se-digital-to-analog-converter/ that "What I heard was reference-level digital reproduction without any sonic bromides." Reference level. Other DACs may be able to drive amplifiers that require stronger output circuitry from their sources, or a lower output impedance (the D90SE is not perfect from these points of view) to avoid either distortion or uneven frequency response, but if the electrical matching is correct, this is reference. That's why I use a D90 to drive the Neurochrome Buffer and the latter drives the Purifis.)

[mocenigo]

8 hours ago, PYP said:

It appears to be some variation of the 1ET400A -- from the NAD website (bolding added):  "NAD’s renowned designers worked closely with Purifi Audio to customise the Eigentakt implementation to ensure every product featuring the technology would meet the high standards NAD is known for. For this reason, NAD manufactures its own Eigentakt modules rather than buy off-the-shelf."

 

The modules they use are indeed 1ET400A's. They look mostly the same and I cannot tell where the differences in the circuits are, if any, but the modulator boards appears to have a little shielding of their own.

[mocenigo]

49 minutes ago, fas42 said:

Actually, the way it works, is that even the cheapest DAC has the potential to reproduce "perfect sound"- that is, extract all the detail in a recording accurately enough to be subjectively satisfying. But, and it's a huge but, implementation is king - and nearly all real world DACs don't get the engineering of the overall box done well enough to not audibly degrade what they produce at the output. One could be lucky, and manage to produce a box, very cheaply, that has minimum weaknesses; the other solution is to throw half a dozen kitchen sinks at the problem, and use outrageous construction to solve most issues; with attendant cost to the consumer ... Wadax is a good example of the latter method.

 

Is the industry there yet, at starting to get sensible about the whole thing? Not really, and so adroit tweaking by the listener is usually needed to get acceptable SQ - "reference level" sound has always been available, since the earliest days; but was and is, normally only realised by those who put the effort into optimising all the things that matter ...

This is a mess of completely unfounded claims, sorry. 

[mocenigo]

(Erased)

[mocenigo]

20 minutes ago, fas42 said:

 

Anyone who states this is so far from where I am, that there will very little chance of reasonable communications ...

says who?

[mocenigo]

6 hours ago, Jud said:

Wait, you’re arguing with Frank when he says there’s little chance of reasonable communication with him?

My bad, sorry.