Buckeye PURIFI 1ET9040BA Amp Review

[Tell]

Just love seeing such a relatively small thing being able to produce that kind of power. Compare that to those huge (and stupidly expensive) audiophile things like a McIntotosh this is really nice to see!

 

[delta76]

Excellent performance all around. Just the price is a bit hard to swallow to me.

My AVR will be just fine. I don't need more than 100wpc. It is inaudible anyway.

 

[DanielT]

Thanks for the test Amir.

..
this thing is endgame through and through.....

It really is.

I agree. There's not much more to say than...

Wow! $2600 is a lot to pay for a pair of mono blocks these days but for a Purifi amp that can put 382 WPC into 8 ohms and be so load indifferent as to deliver 1.4kw into 2 ohms and just smile, it's worth every pfennig. If I ever break down and cash out enough of my 401k to put a pair of Blade 2 Metas in my living room, I know which amp I'll be pairing with them.

Thanks for this one, Amir.

..about the price...$2600 for the endgame
stereo amp is awesome.

 

[Sokel]

That absolutely does it!

Thanks Amir!

(power cube?)

 

[GavriloD]

Would be nice to hear this amp with CLC65, Purifi all over.

​

 

[AudioSceptic]

This is a review and detailed measurements of the Buckeye Purifi 1ET9040BA (second generation?) monoblock amplifier. It was kindly drop shipped by a company and costs US $1,295.
View attachment 501835
A single LED adorns the front indicating power on, protection or fault condition. Back panel has all that one would need for balanced operation:
View attachment 501836
Gain settings are well chosen and inclusion of trigger input for automatic turn on via the source is appreciated.

Buckeye Purifi 1ET9040BA Amplifier Measurements
Let's start with the low gain setting and see what we get:
View attachment 501837
What we get is a big smile on my face! Distortion clocking below -130 dB which is hugely below threshold of hearing. Noise as a result sets SINAD to an excellent 110.6 dB, easily landing the unit in our top 20 amps:
View attachment 501839

Medium and high gain given you the ability to reach full power with more reasonable input voltages but costs you some SNR and hence SINAD:
View attachment 501840
View attachment 501841

Staying with low and medium gains, we see state of the art measurements at full power:
View attachment 501842
View attachment 501843

Vanishingly low distortion remains even at highest frequencies at 5 watts:
View attachment 501844
View attachment 501845

Class D amps can suffer from load dependency but not here:
View attachment 501846
Impedance does not change even up to 100 kHz measurement point!

Story gets even brighter when we consider how much power this lightweight and cool running amp can produce:
View attachment 501862

View attachment 501848
Company specs the amp at 2 ohm so I ran that test as well:
View attachment 501849
Wow!

Even into 8 ohm we have more power than many amps produce at 4 ohm:
View attachment 501850

Muscular power output extends down to 40 Hz, climbing to highest wattage I have measured:
View attachment 501851

Higher frequencies tend to give class D amps a hard time but not so much here:
View attachment 501854

Amp is very quiet on power on but may have some noise on power off:
View attachment 501852

And it is stable on power on:
View attachment 501853

Conclusions
Conventional wisdom says you can have lots of power or finesse. The Buckeye 1ET9040BA tears up that rule and flushes it down the toilet. It has incredibly low noise and distortion, especially at lower gain settings, but also produces copious amount of power, courtesy of its new power supply and capable Purifi amplifier modules. All this in a very cool running package, with features you want at a price that is hard to fathom just a few years ago.

It is my pleasure to recommend the Buckeye 1ET9040BA monoblock amplifier.


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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Stereophile liked Version1 (I assume) <https://www.stereophile.com/content/buckeye-purifi-eigentakt-1et9040ba-monoblock-power-amplifier>. Tiny quibble: why do your power graphs say "both channels driven" for a mono amp?

 

[Dennis_FL]

Wow! Just wow.

 

[Chr1]

If money was no object, I'd buy at least three.
Great amp for sure.

 

[DSJR]

Was hoping for better result at 15kHz, looks like around -85/90dB seems to be the limit of what is achievable in Class D.
No need to remind me it is not audible, but still …

Quite some improvement in measurements vs 1et7040 module, so good.

I have 2 of those and could not be more satisfied, they are driving my electrostats without any issue.

Continued apologies for saying this yet again

It really wasn't that long ago that -80db harmonic and intermodulation distortion was regarded as a good figure for an amplifier and back then, many amps seemed to increase distortions above 10khz too - to -60db or so. Real high end in the UK, was to have SINAD in the 40s or 40s from some US-imported amps, such was a certain reviewer/engineer's opinion-pollution imo.

Build looks good and thoughtfully laid out too. Well done

 

[Geert]

Stereophile liked Version1 (I assume) <https://www.stereophile.com/content/buckeye-purifi-eigentakt-1et9040ba-monoblock-power-amplifier>.

In that review they measured V1 (with Hypex SMPS1200A180 PSU) and the new version. From these measurements we see the max. output power increased from 450 W to 690 W (@4 ohm).

 

[Sokel]

In that review they measured V1 (with Hypex SMPS1200A180 PSU) and the new version. From these measurements we see the max. output power increased from 450 W to 690 W (@4 ohm).

There's still one last step we're anticipating from Purifi:

A crazy tech PSU of their own

 

[Jonas_h]

Great performance!
Would this perform similar in 4-8 ohm use cases: https://nordacoustics.co.uk/product/nord-three-1et9040ba-dm-dual-mono-amplifier/
I can see that the difference is primarily the power supply and it boosts 2 ohm output.

I like dual mono enclosure instead of monoblock and for non-US citizens, Buckeye is not easy to obtain.

 

[Dmitri]

Amazing. No surprise that Dylan & co. implement the Purifi module with spectacular results, but I continue to be completely in awe of what can be achieved nowadays. That max power rating at 40 hz. …1400 plus watts into 2.1 OHm? my god! We’re talking Frankenstein numbers and this amp is definitely alive…No question it will mate well with the most difficult to drive speakers. Great timing too! Can’t really move my current 80 lb amp without some help nowadays. The Purifi, or practically any other Buckeye amp I could carry upstairs in one hand. Again. Amazing.

Kudos to Dylan, Buckeye and Purifi.

And thanks for a great review Amir!

 

[JeremyFife]

Thank you for the review Amirm.

That's a sweet amp! Just a heart-warming review to read. To put the value into context, a pair of these are still cheaper than one Benchmark AHB2: both fine choices for 'big boy' hifi to suit any preference.

 

[Sir Sanders Zingmore]

Can anyone explain to me how “negative headroom” happens

 

[amper42]

This BUCKEYE 9040 amp wins the ugliest design award by far. But, Purifi 9040 is certainly quality hardware.

I wonder what is causing the NINE evenly distributed 10-15dB distortion spikes in the 50 to 8KHz range? Any idea?
Likely not audible but NOT what I would expect from Purifi design team?

 

[nerdstrike]

I approve of this watt to dollar ratio

 

[tineared]

I've been looking at these amps as possible replacements for my Parasound HCA-3500. They are awesome performers, but I'm concerned that they may run out of power when I'm in the mood to let loose
I have been trying to hold out for the Hypex NCx1000 to be released later this year as my current amp is still working properly, but I look forward to the downsizing of my trusty Parasounds as they are all large and heavy and can cook bacon. The ET9040BAs are as perfect as anyone would ever need, I'm just worried about the lack of headroom for those rare but meaningful occasions. Still, I feel slightly more confident about the quality of the components and design of Purifi amps than I do in Hypex amps.
As my Parasounds can testify, I like for things to last and I think these amps are as SOTA as it gets.
Thank you Amir and thank you Purifi and thank you Dylan!

 

[Drengur]

There will always be people in denial about Class D.
I feel sorry for them

Nice little toy. But let me tell you, back in my day they made amplifiers out of concrete and powered them with diesel generators. They were built to last. /s

This is pretty much the last power amplifier I would need (or a pair of them). It is so nice to see how things are progressing.

 

[peng]

A fantastic amp, much better specs/measurements than my NC502MP, the only question I would face if I need one is, if I can't hear the difference between the C$450 3e A7 mono pair and my VTV Eigentakt, NC502MP, I most likely don't need to spend so much more for this SOTA buckeyeamp that also does not have aesthetic appeal. Still, buckeyeamp should be proud, to come up this for less than USD2000 (keep in mind a pair is needed).