Review and Measurements of Purifi 1ET400A Amplifier

[Julf]

To me, the tone seems mean-spirited, and the conclusions a priori seem, well, unscientific. But I suppose you're right, the definition of "meaningful" matters for convos like these.

You definitely have a point. On the other hand, so many of us are totally fed up and frustrated with the "I don't need any math or science, I know what I hear, and if you can't because your gear isn't resolving/expensive enough, or your ears aren't sophisticated enough, that is your problem" crowd that we often over-react.

 

[VintageFlanker]

Audiophonics just put on sale a new fully assembled stereo power amplifier based on dual purifi boards powered by an hypex SMPS1200. price is 1500€

https://www.audiophonics.fr/fr/ampl...ereo-class-d-purifi-2x400w-4-ohm-p-14393.html

Was going to link this one!

Very impressive offering from @Audiophonics, as always. Unfortunately, this make their similarly priced HPA NC400 pointless to me.

 

[maty]

...The price for this Audiophonics is very impressive!

Months ago I commented that it was better to wait for the modules made in Asia to arrive. The Europeans (only first limited batch) implied an extra cost by two modules of $ 500 + benefit of the assembler, plus novelty and exclusivity.

 

[vitalii427]

Don't worry, you can swap the original opamp to your boutique DIP8 opamp later.

"One Analog Devices OP275 AOP per channel is used, they are based on a hybrid Bipolar / JFET technology. bringing precision and musicality. They are mounted on a socket allowing their replacement if necessary."

I'm not interested in swaping opamps and do not want to pay for boutique opamp nonsense.

OPA275 specs:

THD+N 0.006% (SINAD 86.4 dB) not very impressive at least

 

[mocenigo]

I'm not interested in swaping opamps and do not want to pay for boutique opamp nonsense.

OPA275 specs:
View attachment 49908

THD+N 0.006% (SINAD 86.4 dB) not very impressive at least

Maybe one can put two OPA1612's on the modules.

 

[vitalii427]

Maybe one can put two OPA1612's on the modules.

Sure OPA1612 and LM4562 are much better than OPA275. But opamp isn't the only factor. Bad board design and/or voltage regulation can degrade performance significantly.

 

[maty]

That is why we have to wait. If we already have a very good sound we should not fall into the precipitation, like those who spent more than 1,000 euros more with the first Purifi assembled (European modules).

 

[DonH56]

It as a resistance of 100 ohms in series

No, I was talking about the output of the main amplifier, to the speakers, to emulate a tube amplifier circuit. Not the output of the buffer amplifier to the power amp.

 

[Koeitje]

This is complete overkill for my use case, but somehow I just want it anyway . I should probably just set an x amount apart ever month so I have some time to think about it (and maybe they will have a nicer case by then, I don't like the design around the power button).

 

[mocenigo]

Sure OPA1612 and LM4562 are much better than OPA275. But opamp isn't the only factor. Bad board design and/or voltage regulation can degrade performance significantly.

True. I never read a review or a measurement of the Audiophonics buffer, which is also OPA275 based, and probably is the same – and whereas I have never heard anything bad about what they procure, assemble, sell, there seems to be a dearth of information about their own stuff.

 

[mocenigo]

That is why we have to wait. If we already have a very good sound we should not fall into the precipitation, like those who spent more than 1,000 euros more with the first Purifi assembled (European modules).

Quality of their buffer nothwistanding, it seems a decent deal if one does not want to DIY. I am spending a similar amount of money with EVAL1+Neurochrome UB+various power supplies+Custom case, maybe a bit more — and likely getting a better product. But, hey, not everybody likes to solder, measure their cases, use CAD software to design the panels, engineer their own case mods solutions, and order dozens of little bits....

 

[dkinric]

Ghent Audio has some great pre-cut custom case kits, with everything you need to assemble, minus the amp board. I have NO electronics building experience, but ordered their Hypex NC122MP kit and then the amp board off ebay. I got the solderless kit option, and put it together myself for less than $400 total. It's more like building a model, albeit without instructions. However, some googling and patiece paid off, the amp worked first time I powered it up and has worked flawlessly ever since. Sounds great!
https://www.ghentaudio.com/kit/index.html

Also see ASR DIY forum for more details:
https://www.audiosciencereview.com/...ds/ncore-mp-build-using-ghentaudio-kit.10103/

 

[Zoomer]

Very impressive offering from @Audiophonics, as always. Unfortunately, this make their similarly priced HPA NC400 pointless to me.

You're suggesting a price drop?

 

[TabCam]

I'm not interested in swaping opamps and do not want to pay for boutique opamp nonsense.

OPA275 specs:
View attachment 49908

THD+N 0.006% (SINAD 86.4 dB) not very impressive at least

Here I read specs of 0.0006% which converts into -104 dB SINAD which is a lot better. Also more deserving and seems more logical seeing they took care to make it good and cheap enough.

 

[waltzingbear]

the 275 is a nice opamp, but is not new by any sense of the word. I used the 275 in some audio work in the mid 90's, we have come a long way in design since then.

The 1611/12 is among the new crop of opamps that have current fabrication and internal layout that lower distortion and significantly improve drive capability. That one is a factor that attracts me in this application as the input impedance of the Pruifi (and the Ncore amps) is fairly low and wants good drive capability.

 

[TabCam]

Thanks, that makes opamp rolling quite feasable as far as I can deduce. Will look further into the input impedance but quite a few opamps can be considered.

 

[vitalii427]

Here I read specs of 0.0006% which converts into -104 dB SINAD which is a lot better. Also more deserving and seems more logical seeing they took care to make it good and cheap enough.

Good find. This looks definitely better. May be it is the typo in the table.

https://www.analog.com/media/en/technical-documentation/data-sheets/OP275.pdf

But it’s still quite far from OPA1612: 0.000015% THD

 

[JimB]

Good find. This looks definitely better. May be it is the typo in the table. ...

It does have relatively high voltage noise. At first, I'd have said you were comparing THD + N to just THD, but I note your highlights from the description. THD won't net quite that good if you are using some gain (not just 1).

 

[TabCam]

NordAcoustics has a new and far cheaper stereo Purifi amplifier for £979,- ex. VAT. That price translates to a little less to the Audiophonics offer, albeit probably without 12V trigger. It uses the OPA1612 so for those wanting a better opamp without DIY certainly an option.

 

[Matias]

Indeed, very inexpensive for such an amp.
https://www.nordacoustics.co.uk/product-page/nord-three-1et400a-stereo-amplifier