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Review and Measurements of Purifi 1ET400A Amplifier

maty

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Recently I read about it but I do not remember where or who, maybe it was Bruno himself. I do not remember the answer either.
 

g29

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I wonder why they test at 18.5 + 19.5 kHz rather than the standard CCIF at 19+20.
Any idea?

Maybe the .5's makes the harmonics stick out and easier to identify.

Interview Questions with Bruno and Lars.

"... Lars: Like a 20kHz THD test in its own right is not very useful because the harmonics are inaudible. So you do an IMD test with 20kHz and 19kHz tones and all of a sudden the whole audible spectrum clutters up with distortion. The silly thing is that the standard CCIF test that this signal came from then ignores all of that and only looks at the lone second order product at 1kHz… You have to look at the whole spectrum and that’s really enlightening. It’s one of the major tests that really tell you which is the better amp. Probably a reason why this test isn’t commonly included in amplifier data sheets. ..."

"Note 2: At higher audio frequencies there are not enough harmonics left in the audio band to make a meaningful THD measurement. High frequency distortion is therefore determined using an 18.5kHz+19.5kHz 1:1 two-tone IMD test."

Bruno explains the reasoning in this very thread.

Thanks much for exact post..

"... In fact his version is even neater, he uses 19.5kHz and 18.5kHz, making sure that even order products sit at even multiples of 500Hz (from 1kHz upward) while odd products sit at odd multiples of 500Hz, from 17.5kHz down, potentially fitting 37 distinct IMD products inside the band. This refinement doesn't make much difference with the 1ET400 amp of course since there aren't that many IMD products poking up over the noise floor. ..."
 
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maty

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Thanks to both.

Must be a thing of the Mediterranean hot (humid heat) that softens my brain. And I am sleepy, it is almost the 23 pm 11 PM!
 
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amirm

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Hi @amirm , I think the first "without" should be "with" in your original post.

BTW, thanks for testing this board.

"You get full power with as little as 1.5 volt without the extra gain but need 11+ volts without it. "
HI there. Thanks for the note. Fixed it.
 

Fedde

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This new Purifi amp "sounds" very interesting! :cool:

@Bruno: is there a plan to offer DIY mono amplifiers as well? I would expect that many potential customers have NC400 based mono blocks (either with the standard Hypex casings or alternatives, e.g. from Ghentaudio). So it would be cool if hosting boards with mono input buffer would become available, hopefully also useable with the SMPS600N400 and fitting in the housings (this may be tight though). If there is a reasonable cost associated with this, this may be an interesting upgrade path for many users...

Fedde

1567678384262.png
 

Matias

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@Bruno Putzeys could you please share with us the THD+N x power graphs of the 1ET400A, in 8, 4 and 2 ohms, with the typical 100Hz, 1kHz and 6.67kHz colored lines? Thanks in advance! :)

I will answer myself for anyone who is also interested.

It was pointed out to me (thanks @March Audio ) that the 1ET400A product brief (see attached PDF) does not have the power x THD+N graph with the 3 colored frequency lines as the other manufacturers, but it has a frequency x THD+N for 3 power levels, as shown below. We can see that there is no rising THD+N on the highs, at least up to 100W, like we see on the 6.67kHz of most ICEpower and Pascal modules.

Purifi 1ET400A THD x f.jpg
 

Attachments

  • 1ET400A - Product Brief (1.01).pdf
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Matias

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This new Purifi amp "sounds" very interesting! :cool:

@Bruno: is there a plan to offer DIY mono amplifiers as well? I would expect that many potential customers have NC400 based mono blocks (either with the standard Hypex casings or alternatives, e.g. from Ghentaudio). So it would be cool if hosting boards with mono input buffer would become available, hopefully also useable with the SMPS600N400 and fitting in the housings (this may be tight though). If there is a reasonable cost associated with this, this may be an interesting upgrade path for many users...

Fedde

Hypex launched a buffered module for DIY (NC400), but since manufacturers wanted to differentiate themselves, they offered then a somewhat similar bufferless module (NC500).

I speculate that, from this previous market experience, Purifi decided to offer a single bufferless module (1ET400A) that pleases both manufacturers and also DIY by offering the optional buffered I/O board. Should be easier to satisfy both markets with a single module.

So from my guesswork I suppose no single buffered module from them to replace NC400s...
 

boXem

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This story of custom buffers is only for pure amplifiers, which, I believe, are not the biggest part part of the amplification market. Most people think "integrated amplifier" when they hear "amplifier".
If a manufacturer wants to make a "Devialet Expert like" box, with DAP, DAC, ..., having no onboard input buffer offers higher flexibility at a lower cost.
 

Matias

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Marantz PM10 is an example of integrated amplifier using a custom preamp for the NC500 based power section ($8,000).

Bel Canto ACI 600 is an integrated amplifier with custom preamp, DAC and streamer, also using NC500 based power section ($25,000!, measurements).

I suppose both would be more than happy to switch to 1ET400A when its avaliable and release a Mk.2 version of both integrated amps.

If only the 1ET400A used the same power supply as NC500, upgrades woule be trivial, just swapping modules, but no, the 1ET400A needs a different voltage than NC500...

Below a picture of the inside boards of the ACI 600, showing the twin NC500 modules on the left.
aci internal 4.jpg
 
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g29

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So when will these little critters be roaming free in the DIY wild ?
 

Matias

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Q4 2019 is just around the corner. :)
 

Julf

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Just bought the Purifi amp from Nord. I have opted for the Sparkos Opamps. I also have the NCore version with Sonic Imaginery opamps, which looks just the same:

You really seem to like to combine extremes - very transparent Hypex and Purifi on one hand, tubes and lampizator on the other. :)
 

maty

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And?

Some would be grateful if you would start a specific thread where you can comment on the sound quality, the current one and after a few hours of burning of the fat condensers. Obviously, 1ET400A vs NC500.
 

VintageFlanker

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Just bought the Purifi amp from Nord. I have opted for the Sparkos Opamps. I also have the NCore version with Sonic Imaginery opamps, which looks just the same:

tg0Zpo.jpg


x3qj5Y.jpg
Looks like a very, very nice room :). Nice system too... But... What the hell are these power chords ?!?:eek:
where you can comment on the sound quality, the current one and after a few hours of burning of the fat condensers.
Hum. No. Please don't.
 
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