Buckeye NC252MP Stereo Amplifier Review

[Rick Sykora]

Why?

so it is easier for others to find and not in a review thread?

 

[AdamG]

Yes, but they are usually helpful. Will request assistance. Thanks!

Will be working with Rick to relocate these side topic discussions. Please stop posting until we relocate the side conversation posts to a different thread. If you continue off topic posting in this review thread. Your posts may be deleted without further warning.

Thank you for your cooperation and understanding.

 

[AdamG]

Multiple posts relocated here:

Amplifier measurements may require improvement

Which kind of music did you use? -Which tracks? At that high level I used the following album, didn't pay attention to which track, but a few tracks anyway.

www.audiosciencereview.com

 

[DualTriode]

What are you calling "brick wall" filter? Here is the response of AUX-0040:

That is flat to nearly 100 kHz and then goes down by 500 KHz. The filter requirement is due to front-end of Audio Precision analyzer not being able to handle the high frequency noise. It upsets its auto-scalar among other things. Other analyzers don't need such filters.

Hello,

This is what brick wall filtering is about.

See the Benchmark post below.

Thanks DT

Laboratory Use of the Benchmark AHB2 Power Amplifier

SEAS driver test system uses Benchmark AHB2 SEAS, a well-known manufacturer of high-quality loudspeakers, selected the Benchmark AHB2 as a key component for use in testing loudspeakers. They created an innovative test system that measures loudspeaker motor strength and moving mass with higher...

benchmarkmedia.com

 

[Ajax]

I don't give a dam' what the shit looks like, just make sure the price reflects it.

What keeps me away from class D (as totally non technical guy) is lack of speaker outputs for bi wiring, that is my guilty pleasure, be it effective or not.

What would stop you buying a 4 channel amp from Buckeye with 2 x hypex 502 for the woofers and 2 x hypex 252 for the tweeters? Dylan will mix and match for you with a cost of ~$1,000 and a massive amount of clean power. Still "reasonable" IMO.

Buckeye Amps

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

Good luck

 

[Overseas]

Well, exactly 'mix and match' is what keeps me away. I am a non audio technical guy so I stick with Yamaha AS1100 for the moment, I mean a turnkey solution.I run away when I hear about using a screwdriver to change 'gain' or whatever. I am an audio enthusiast, not a DIYer, you know.
I am not kidding, just giving you a lay perspective on class D.

 

[Buckeye Amps]

Well, exactly 'mix and match' is what keeps me away. I am a non audio technical guy so I stick with Yamaha AS1100 for the moment, I mean a turnkey solution.I run away when I hear about using a screwdriver to change 'gain' or whatever. I am an audio enthusiast, not a DIYer, you know.
I am not kidding, just giving you a lay perspective on class D.

Mix and match would just be me assembling two different amp modules in one case. Absolutely nothing different would need done on your end.

 

[Julf]

Well, exactly 'mix and match' is what keeps me away. I am a non audio technical guy so I stick with Yamaha AS1100 for the moment, I mean a turnkey solution.I run away when I hear about using a screwdriver to change 'gain' or whatever. I am an audio enthusiast, not a DIYer, you know.
I am not kidding, just giving you a lay perspective on class D.

Bespoke/custom/variations has nothing to do with class D.

By the way, when you select options when buying a new car, it is also "mix and match".

 

[howard416]

How does the auto-turn-on work? Is there a low power standby mode on the power supply? Does it add any distortion when it is in auto mode?

 

[Apollon Audio]

I wonder who makes the cases for Apollon's pricier offerings?

We manufacture all our enclosures in house from raw aluminum.

 

[Rick Sykora]

How does the auto-turn-on work? Is there a low power standby mode on the power supply? Does it add any distortion when it is in auto mode?

In testing the prototypes, the auto-on required some refinement. Not sure about Buckeye’s other amps, but the detection circuit is always present in his MP series amps. The switch position just tells the processor to act upon the input signal level and bring the power from standby to full (when triggered). My measurements showed the final detection circuit to be transparent. Since the circuitry is always present, pretty sure Amir’s measurements also would show any major issue.

I use auto-on on my Buckeye NCx500 as my DAC does not have a trigger out. Hope this helps!

 

[David_M]

This is a review and detailed measurements of the Buckeye NC252MP balanced stereo class D amplifier. It was kindly drop shipped to me by a member and costs US $575.
View attachment 315040
The amp is almost the size of a loaf of bread and literally weighs nearly as much! Amazing how far amplification technology has come. The package is made to be economical and intended to be heard than seen. Back panel is what you expect to see with notable inclusion of trigger input to automatically power the amp from the source:

View attachment 315042

If you are not familiar with the tests that are about to follow, please watch my video on understanding amplifier measurements.

Buckeye NC252MP Amplifier Measurements
We start with our 5 watt dashboard into 4 ohm:
View attachment 315043

Nice and competent, landing in our top bracket of all amplifiers tested:
View attachment 315045

View attachment 315046

Noise performance is excellent:
View attachment 315047

Frequency response is flat in audible band and load independent (not all class D amps are):
View attachment 315048

Crosstalk is excellent:
View attachment 315049

Intermodulation distortion is very low:
View attachment 315050
View attachment 315051

You buy the amp for power so let's see how much we have:
View attachment 315052
View attachment 315053

Nice to see it meet spec.
View attachment 315054

The amp passes reactive loads at 8 and 4 ohms. At 2 ohm, it would go into protection before reaching peak power:
View attachment 315055
View attachment 315056

Non-linearity does increase at higher frequencies, and there is noticeable power drop at 20 Hz:
View attachment 315057

EDIT: a later run of this test produced lower distortion at 20 Hz. I meant to post it but made a mistake and post the older one:

There is good bit of power on/off noise:

View attachment 315058

Amp is stable on power up:
View attachment 315059

Conclusions
The NC252MP delivers the promise of the hypex class D module, producing competent and above average performance in every measured category. It is light and easy to carry. And produces good bit of power without much heat.

I am going to recommend the Buckeye N252MP.

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

Its baffling to me why this amp cannot produce a 20Hz signal (or lower?) at full power, but instead goes into protection mode.

Also the tested amp can't handle a 2 ohm load (resistive, inductive or capacitive) , despite what the manufacture states.

What's going on with this amp???

 

[Buckeye Amps]

Its baffling to me why this amp cannot produce a 20Hz signal (or lower?) at full power, but instead goes into protection mode.

Also the tested amp can't handle a 2 ohm load (resistive, inductive or capacitive) , despite what the manufacture states.

What's going on with this amp???

Both of these points were discussed extensively in the thread and cleared up/better explained by Amir.

 

[DonH56]

@Buckeye Amps -- This is going to keep coming up. My suggestion would be to create a file with links directly to the appropriate posts and/or explanation that you can open and copy/paste whenever it comes up again.

That is what I have for my tech threads -- a text file on my PC with the post links so I can just copy them into a new post as needed. Too lazy/stupid/time-constrained to search every time.

FWIWFM - Don

 

[Descartes]

We manufacture all our enclosures in house from raw aluminum.

Sweet do you have a CNC machine?
Too bad you aren’t based in the US

 

[Descartes]

Both of these points were discussed extensively in the thread and cleared up/better explained by Amir.

Aren’t KEF speakers hard to drive since they are 4 Ohms and go down to 2 Ohms?

 

[Apollon Audio]

Sweet do you have a CNC machine?
Too bad you aren’t based in the US

Yes, we have two big CNC machines, laser engravers, 3D printers and UV printers.

 

[Buckeye Amps]

Aren’t KEF speakers hard to drive since they are 4 Ohms and go down to 2 Ohms?

Down to 2ohms would be considered hard to drive, yes. But our amps have no issues doing so.

 

[rdenney]

At this price, it seems like a class AB killer.

Except for not having any headroom and its 8ohm power is not stupendous. And most of my speakers are nominally 8 ohms and my living room speakers are small but fantastic stand mount Mirage MRM-1 (not a dipole) and have pretty low sensitivity (84-86db). Seems like headroom would be desirable for such speakers in a largish room, even with a sub crossed at 60-80hz.

Or is it not an issue in practice? I have run the speakers with amps ranging from 120 watts to supposedly 300 watts (though it was a carver sunfire 2x300 and I don’t buy the power claim) but always had amps with lots of headroom and high damping.

For example, the Schiit Vidar doesn’t have appreciably more power at 8ohms—though it does have headroom , measured well but not as well as this, and is almost $200 more.

Or does one really need to go up a pricing tier or two to $1200 to $3000 range for the latest ncore and purifi based units? Such as a pair of Nord classic monoblocks?

No, you might just need to consider the NC502MP version of this amplifier from Buckeye, which provides twice the power. Twice the power, of course, means only a 3 dB gain in power output and therefore maximum listening level. I judge the 502 to provide 330 Watts into the 6 ohms at which my Revel F12's are nominally rated, reported at the knee of the distortion graph (meaning--better than 1% distortion--more like a hundredth of that).

It's about $175 more expensive than the amp being tested in this thread. The only reason to purchase it would be in case one wants the additional power to drive inefficient speakers to high listening levels.

But headroom is poorly specified. My former B&K Reference 125.2 amplifier, a class A/B design, is excellent. It's distortion level is higher at rated power (by a factor of about 10--probably not significant), and it lists a "headroom" specification of 1.2 dB, whatever that means. Assuming that means the ability to fill waveforms requiring higher voltage than would be implied by the continuous power rating for some brief period of time, that would mean a "peak" power rating of maybe 180 wpc. I'm assuming that means a power output at something more like 1% (-40 dB) for a brief period. That amp would be distortion-limited, not power-supply limited as is the case for amps powered by regulated switching power supplies. That assumption has never been measured that I've been able to find, so assumption it remains. In any case, the amplifier reviewed in this thread provides more power, and the 502 version much more power, even taking the "continuous" power output with the assumption of no headroom.

Rick "not seeing much that's more powerful at just about any price" Denney

 

[rdenney]

Reading this thread, I'm reminded of something I heard from a reviewer of the work of a standards committee back in the day: "You've now provided enough documentation that we can provide a detailed review." Freely translated: Now that you've provided some detail, we have lots more that we can nit-pick.

It seems to me there is more published testing of the Ncore modules than just about any other amps I've ever been interested in. I'm not sure it's the integrator's responsibility to reiterate all of that when it is all so easily found in any quick search.

Rick "reviewed all of those published results before buying a Buckeye NC502MP amp" Denney