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Buckeye Purifi Eigentakt 1ET9040BA monoblock power amplifier Stereophile Measurements

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Hope we’ll get a clear explanation from the designer/manufacturer of the module. Or not? ;)

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Not at all. My conclusion has nothing to do with what the vendor has claimed. I look at all the data, apply my subjective impression of features and build quality, and give a recommendation. A 15 pound amplifier producing 450 watts with incredibly low distortion is a great find and would provide amazing performance for users. No way do I want to tell people not to buy it because of what they say on their website. I am not a website police.

Yes, I make a few exceptions here and there but the above is the rule.
That’s an interesting stance. I would have thought that vendor specs and price were two key contextual elements to any product review?

Not a criticism of your fine work, just my POV.
 
I suppose the same fault is responsible for the power figures
Or the power supply used. The issue mentioned seems to be related to HF distortion performance. Filter coil core? I am curious.
 
Or the power supply used.
You mean even if working right?Yes for the 2 Ohm as the lower efficiency of the module combined with PSUs own losses is not enough if it's rated for 1200 W max.
But I believe there's an option offered for another more powerful supply (not with the same safety certifications,regulations,etc as the Hypex one though,that's why I asked about the one used by Purifi)

(9040 is at my very short list but I want it the way I want it and the paranoid me will not find as such except Purifi makes it's own PSU )

Edit:Also let's not forget that power losses are enormous up there,it probably needs some serious cooling PLUS the cooling for PSU which in most cases is worst than the most of the Purifi modules.


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Purifi and their latest ass-covering disclaimers. Wow.

What's next? "We made a mistake with continuous power. We thought it was just a millisecond or two. Sorry for the inconvenience and we are working with our partners to ensure you have no idea this ever happened. And by the way, these are not the amplifiers you're looking for..."
 
Purifi and their latest ass-covering disclaimers. Wow.
Just wondering, is your permanent negativeness specifically related to Purifi (and Hypex) or just class D in general?
 
I started a thread on Purifi's facebook page drawing their attention to the review and the conversation here. They replied with an explanation as per the above post. I am hoping they either provide the serial number range of affected modules on Facebook or alert their customers so that early adopters can verify that they do not have a defective module.
 
FWIW: we have our own data from months ago showing no issue with the amp going into protection during power sweeps and also meeting the power spec goals.

As I have said in our official thread, we will be doing more testing in the new year to further back up what we have already observed on our end.

I am in no way saying JA did anything wrong, is faulty, etc. It is something that at this moment can't be explained and is at odds with previous data. So being the trained scientist I am, will not begin to speculate or draw conclusions until more data is collected and added to the mix.
Thanks Dylan! Enjoy your time off and have a Merry Christmas! Meanwhile, many in this community will be busy burning down your castle over one review sample that seems faulty. I mean why wait when one can instantly post negativity on forums? The very same forums where manufacturers also do a pretty good job of answering questions of their customers. Makes me wonder why ANYONE would want to build anything nowadays. This hobby isn't dying, we're killing it.
 
As I have said, patience and an adequate amount of data points goes a long way in science.

Luckily, the Stereophile monoblocks were the only affected builds we had shipped with this defect. And while people will ask why we didn't thoroughly test it before sending out for a high-end review...because I do not cherry pick. Our measurement testing involves picking a few components whenever we receive a new batch (amp modules, SMPS', buffer boards, etc) and testing those. It just so happens we didn't pick the bad module from the early batch to test.

All final built amps are tested for functionality and listening impressions (while every so often a random final build is also measured), which these monoblocks did pass (as evidence by Kal's subjective impressions that in practical use it was as superb sounding as expected).

I have reached out to Kal/Stereophile in case they would like to re-measure a new monoblock but I am not at all requesting or demanding that they do.

I will also, as already mentioned, be providing new sets of measurements to hopefully appease those who still want to jump to conclusions of bad engineering on our end.

Thank you all and Happy Holidays!
 
Thanks Dylan! Enjoy your time off and have a Merry Christmas! Meanwhile, many in this community will be busy burning down your castle over one review sample that seems faulty. I mean why wait when one can instantly post negativity on forums? The very same forums where manufacturers also do a pretty good job of answering questions of their customers. Makes me wonder why ANYONE would want to build anything nowadays. This hobby isn't dying, we're killing it.
You seem to be saying that the forums, or rather certain members of ASR, are nitpicking and that one should keep quiet even if an amplifier does not meet the objectives announced by the manufacturer and designer (not the assembler). So here, it seems that the problem stems from a non-existent quality control at Purifi, and the assembler is apparently exonerated, all thanks to the perspicacity of a few ASR members. By the way, I remind you that Stereophile found nothing to criticize about the issues with this amplifier which did not match the specifications ..
 
Luckily, the Stereophile monoblocks were the only affected builds we had shipped with this defect.
Did you verify that this defect existed on those amps?

Thanks for digging into this.
 
Had Purifi recalled any units? Was anyone outside Purifi aware of the faulty batch? It seems like a huge coincidence that the one unit that was not recalled "in time" was the one that made it to the reviewer... I think Purifi should explain further, if they haven't yet.
 
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You seem to be saying that the forums, or rather certain members of ASR, are nitpicking and that one should keep quiet even if an amplifier does not meet the objectives announced by the manufacturer and designer (not the assembler). So here, it seems that the problem stems from a non-existent quality control at Purifi, and the assembler is apparently exonerated, all thanks to the perspicacity of a few ASR members. By the way, I remind you that Stereophile found nothing to criticize about the issues with this amplifier which did not match the specifications ..
Perspicacity.. Hardly. The manufacturer stated his intention of looking into these issues discovered during the review. Didn't need arm-chair quarterbacking for him to do so. Also, your assumptions of "non-existent quality control" is exactly what I was referring to.
 
Did you verify that this defect existed on those amps?

Thanks for digging into this.
We will be, yes. I more meant we know because of the batch involved from that shipment from Purifi (which was a very small pilot quantity so easy to trace).

I know some people want to think I am either being lazy or not taking this seriously due to my "slow" reaction time but that's because having all the facts is the most important step of something like this. So it is best to just let those people talk out loud into the air rather than play a game of whack a mole at every post, accusation, insinuation, etc.
 
The important thing, to me, is that no customer is affected/need not worry. It sucks it happened to a review unit but nothing I can change (no crying over spilt milk). All I can do (as has been planned) is to show that our design works and measures as expected and reaffirm this is an isolated incident.
 
It took quite a while for the 1ET9040 to become available from Purifi. The Thread New Purifi amplifiers coming started on May 22nd 2022! This may have been a tricky module to get finalised and then ensure production quality. When I used to do benchwork on amplifiers I would taken quite a lot of safety care with something potentially capable of running at 90V and 40A.
 
I have reached out to Kal/Stereophile in case they would like to re-measure a new monoblock but I am not at all requesting or demanding that they do.

Discussed this with Kal and Jim Austin this morning, Dylan. We are in agreement that you should ship a pair of amplifiers to me for measurement. If both are behaving correctly, Kal will then audition them and Stereophile will publish a followup.

I'll email you with my shipping address.

John Atkinson
Technical Editor, Stereophile
 
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