Buckeye PURIFI 1ET9040BA Amp Review

[Sokel]

and Audiophonics in France (and Europe).

And soundimports for simple modules in a decent small case.

 

[AudioSceptic]

And soundimports for simple modules in a decent small case.

Yes, but I was limiting the list to those with good independent measurements.

 

[AudioSceptic]

Also Boxem

Thanks, missed that one!

 

[Descartes]

It seems that the best "geographical" options are Buckeye in the US (and Canada?), Nord in the UK (and Europe), and Audiophonics in France (and Europe).

At least until tariffs go away hopefully!

 

[oleg87]

"Probably"? There's a "lab report" page:

View attachment 504069

Alex

Good lord, people buy this crap? A far better space heater than amp it seems.

 

[Fahzz]

At least until tariffs go away hopefully!

SCOTUS decision forthcoming any day now.

 

[David_M]

There is no requirement that the top of the volume dial be able to deliver max power. In fact, often that is not desirable.

Top of the volume control provides the highest SNR specs for every amplifier, assuming we are still in linear operation (i.e., not clipping).

 

[maser77]

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:
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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:
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Vanishingly low distortion remains even at highest frequencies at 5 watts:
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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:
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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/

You can't go wrong buying a Buckeye Amp from Dylan. Great product and support. I wanted the Purifi 1ET6525SA for my secondary system but wanted monoblocks to put the Amps close to the speakers to minimize total impedance at the speaker input for maximum Damping factor. At the time this configuration was not listed on the web site but Dylan put together the monoblock configuration for me and it's now available as an option. I'm using KLH Model 5's in this setup and the 1ET6525SA's 230W @ 8 ohms is more than enough to drive the speakers to volume levels above comfortable listening levels without any audible distortion from the amplifier. A more affordable option if your speakers don't need the massive power output of the 1ET9040BA. BTW, my main system uses a Benchmark AHB2 (rated 100W per channel at 8) and it comfortably drives a pair of high end Revel's. More power is perhaps desirable but not always necessary.

 

[xaxxon]

8 ohms "both channels driven" on a monoblock?

 

[xaxxon]

Was hoping for better result at 15kHz, l

why?

 

[xaxxon]

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?


View attachment 501885

that's the great part -- if you want to pay more for a case for something you never need to look at or touch, you can get that from somewhere else with the same hardware inside. For those who don't care what it looks like, it's an option to not pay for it.

 

[welwynnick]

Thanks Amir, I've been looking forwards to this review for some time.
The SINAD was a touch disappointing, but the HF linearity and load tolerance were brilliant.
This might go to set the highest ever vote.

This is getting a bit nerdy, but I make no apologies. I'm having fun (though I'm mindful that somebody recently told me to get out more).
I wondered if this 1ET9040 test returned the best 19 / 20kHz IMD result, and I started looking around for any better results.
Firstly, John Atkinson got very good results from the Buckeye 9040, Benchmark AHB2, Sim Audio Moon 861 and Linn Klimax 800.
They're not strictly comparable, but Amir's results for the Buckeye and the Benchmark were very similar. He also got great results from the Apollon 6525 and Topping B100.

The Buckeye 9040 has particular strengths like high power and superb load tolerance.
The weakness of any class D amplifier is high frequency linearity, and I've been focussing on this weakness - comparing Purifi at it's worst, if you like.
I've compared it with the best digital and linear amplifiers that I have ever come across.
It seems to me that in this respect the Buckeye 9040 is narrowly the best of the lot.

 

[Brian Beck]

I have a pair of rebuilt Apogee “Full Range” ribbon speakers. These 350-pound monsters require lots of power into low impedances, and they must be bi-amplified (despite having three drivers per side). For years I had been using four 250W channels of Audio Research tube goodness, which worked great.

But, out of curiosity, and out of respect for Bruno Putzeys’ engineering prowess, I decided to try bi-amplifying with four Purifi-based Class D amplifiers. I assembled my own four chassis with Purifi 1ET9040BAs and the same Micro Audio PSs as tested here. (I had also bought four Buckeye amps exactly as tested here, to drive other speakers around the house.)

The Apogees love the new juice being fed to them, sounding articulate, detailed, impactful, yet sweet. The Audio Research amps might reveal a bit more about the sound stage, and deliver more fetching string tones at times, but not enough better in some little ways to keep the throne.

The image is of left channel, with my two Purifi ands perched on the Audio Research D-250 MkII Servo stereo amp.

 

[maser77]

8 ohms "both channels driven" on a monoblock?

Hi xaxxon. If you're referring to my post I'm using two monoblocks, one for each speaker.

 

[AkodoGilador]

Hi xaxxon. If you're referring to my post I'm using two monoblocks, one for each speaker.

He's referring to Amir's Power vs Distortion graphs, eg:

Alex

 

[sapphireracing]

Which is why I never upsell anyone who is looking at the 2ch options.

Can confirm and appreciate this - I was ready to spend the extra for three 9040s but Dylan indicated it would make essentially no difference driving a pair of 226Be and a 426be in a moderately sized room.

Very happy with the 3ch Buckeye 6525 I bought instead.

Still remain tempted … because all the power!

 

[Head_Unit]

, I agree that the amp question is a solved problem. Between the various Purifi and Hypex offerings, set your budget, determine power needs and figure out what looks good in you living room.

now we need it distilled into like WiiM Amp style devices with like 300W/channel for $500 or whatever. HDMI-in amps which can connect to the TV and use the TV remote, but with massive low impedance power. AND still low distortion and noise. It's the next frontier!

As for this congratulations Buckeye making it onto the very short list* of amplifiers that actually double their power at clipping (not the specs, the actual measurement) and this one may be a trailblazer, I don't think the others can do it into 2Ω.

*I'm not at home so I can't look at my saved files. Some all-in-one Devialet, and I forget what else. Most everything rated to double power actually just under-specs the higher impedance, certainly for zillions of automotive amps we measured.

 

[Endibol]

It seems that the best "geographical" options are Buckeye in the US (and Canada?), Nord in the UK (and Europe), and Audiophonics in France (and Europe).

Don’t forget Apollon!

 

[Head_Unit]

Don’t forget Apollon!

Seems nice as well. What does shipping/tariffs cost from Slovenia to USA? EU? Etc?

 

[Endibol]

Seems nice as well. What does shipping/tariffs cost from Slovenia to USA? EU? Etc?

Slovenia is part of the European Union. Tariffs 15%, shipping costs practically the same as those for audiophonics in France.