Buckeye PURIFI 1ET9040BA Amp Review

[SorenTyson]

Fantastic. Buy a pair and never worry about amp performance.

One of the rare cases where everything lines up: power, quality and a reputable seller.

Not expensive at all for ticking all boxes - especially when you remember what amplifiers used to cost.

 

[Power Pop 23]

Thank you Dylan at Buckeye Amps and Amir.

A reminder that Buckeye Amps offers the option of colors other than Black:

Buckeye Amps Colors

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

 

[Buckeye Amps]

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

Aww, thank you!

 

[Geert]

There's still one last step we're anticipating from Purifi: A crazy tech PSU of their own

That was on their roadmap at the moment they released their first amplifier board. I guess they concluded others could also design a capable SMPS.

 

[ObjectiveSubjectivist]

That's some serious power.

 

[Billy Budapest]

Aww, thank you!

I don’t see anything wrong with the case design.

 

[Power Pop 23]

A previous owner of my house added wiring and a panel box to support a (now removed) whole-house electric furnace.


How much electrical power would the Buckeye PURIFI 1ET9040BA amplifier draw at near maximum power output ?

 

[Repdetect]

Go Dylan!

 

[JohnnyNG]

The latest endgame amp, very nice!

 

[JDS]

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.


------------
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/

The availability of affordable "high-powered" tube amps (30-50 watts) in the 1950s enabled the development of revolutions like the acoustic suspension loudspeaker. After inflation, these kilowatt amps are cheaper than mid-50s Dynas (and perform far better). What wild new new speaker tech could that much power enable?

 

[AudioSceptic]

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.

Audiophonics also has their 2x 1et9040ba amp <https://www.audiophonics.fr/en/power-amplifiers/audiophonics-hpa-dm750et-1et9040ba-p-18943.html>

 

[Chagall]

What wild new new speaker tech could that much power enable?

It’s not so much about new speaker technology. What this provides is clean power and high SPL for big rooms, with a 5-6 meter listening distance. Most speakers today are low-sensitivity, low-impedance designs, so I think it was about time.

 

[tineared]

I don’t see anything wrong with the case design.

They are utilitarian, they are not ugly

 

[Power Pop 23]

Aww, thank you!

IIRC, Dylan mentioned that a very small percentage of his customers opted for a color other than Black and that surprised me.

I regard the surcharge and wait time as reasonable and thank Buckeye Amps (and KEF) for bringing more color to high fidelity.

Sadly, the option of an anodized aluminum finish is no longer available.

 

[temujin44]

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.


------------
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/

omg 2 horsepower into 2 ohms!

 

[boXem]

Congrats @Buckeye Amps !

 

[Joe Smith]

I can't imagine ever needing that much power, but these are truly impressive specs and test results! Buckeye is doing some great work, for sure.

 

[marcom22]

Great amp, the Purifi 1ET9040BA will be my next choice (sorry about the new Hypex module, but the Purifi rocks everything
). Thanks, Amir, for the better explain and separation of the gain graphs (even with voltage input details, e.g., at full power)... I really appreciate it.

 

[phoenixdogfan]

Aww, thank you!

I keep harping on it but just buy two of these, and put them in one of these.

 

[kyuu]

This BUCKEYE 9040 amp wins the ugliest design award by far.

Looks fine to me.

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?

You're calling spikes roughly -120dB down when pushing 5W into 19/20kHz likely inaudible?