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boXem ARTHUR 2408/N2 Review (Stereo Amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 1 0.4%
  • 2. Not terrible (postman panther)

    Votes: 9 3.9%
  • 3. Fine (happy panther)

    Votes: 134 58.8%
  • 4. Great (golfing panther)

    Votes: 84 36.8%

  • Total voters
    228

sarumbear

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Let's leave it at that and drop the topic then, I'll enjoy my music and you enjoy your music, as long as we're having fun in the end it doesn't matter ;)
Hurrah! You sir, are a gentleman. Thank you.
 

doug2761

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Conclusions
The Arthur 2408 comes in an attractive and differentiated package with very high quality connectivity. Measured performance is hugely above average although not state of the art. I could not find any weakness in its performance no matter which way I measured it -- a sign of excellent engineering. The cost is up there though for the level of power you get. Seeing how company is represented here (@boXem | audio), support should be easy as well.
It's nice to see that a few companies have elegantly solved amplification for home audio. Pretty good time to be assembling a system. Multi kilobuck systems aren't measuring better these days.
 

Spocko

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It's nice to see that a few companies have elegantly solved amplification for home audio. Pretty good time to be assembling a system. Multi kilobuck systems aren't measuring better these days.
Agreed, I'm a little tired of the little space heaters from the kilobuck Class A/B amps weighing over 40 lbs.
 

Dmitri

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Agreed, I'm a little tired of the little space heaters from the kilobuck Class A/B amps weighing over 40 lbs.
Oh I dunno...I’m gonna kind of miss the beast in the AV room. Helps make up for the other inadequacies... and I can’t afford the proverbial Porsche to fill in.. ; )
 

hyfynut

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This is a review and detailed measurements of the boXem ARTHUR 2408/N2 stereo class D amplifier. It was kindly sent to me by a member and costs €649.00 Tax excluded (US $735).
View attachment 172964

I really like the differentiated look of the unit with custom front panel and white case which you can see better in this shot:

View attachment 172979
Notice the ultra high quality and large binding posts and nice power switch. Input is only balanced XLR as you see. I believe the heart of the unit is Hypex NC122MP.

boXem ARTHUR 2408/N2 Measurements
The unit stabilized quickly with its performance hardly changing (I optimized the cabling after this measurement so don't worry about channel difference):
View attachment 172972

Here is our dashboard:
View attachment 172966

This level of distortion and noise (SINAD) nicely landed the amp into our "excellent" category:

View attachment 172967

Signal to noise ratio was excellent, achieving better than CD dynamic range at just 5 watts of output:
View attachment 172968

Typical of Hypex amplifiers (in a good way) is lack of load impedance dependency which plagues many budget class D amplifiers:
View attachment 172969

The 2408/N2 achieved one of the lowest crosstalk I have measured:

View attachment 172970

Multitone results are very good as well:

View attachment 172971

Let's see how much power we have:
View attachment 172974

Not a ton but it is above average as far as noise and distortion. Allowing a bit more distortion we get:

View attachment 172975

Which is right on the money as far as company specifications. Here is 8 ohm performance:

View attachment 172976

Checking for frequency dependence we see well behaved response:

View attachment 172977

But note the loss of power with 20 Hz input.

Finally, here is the switching and ultrasonic performance:


View attachment 172978

I checked the unit for temperature after all the test and could barely feel any rise above room temp on any of the surfaces.

Conclusions
The Arthur 2408 comes in an attractive and differentiated package with very high quality connectivity. Measured performance is hugely above average although not state of the art. I could not find any weakness in its performance no matter which way I measured it -- a sign of excellent engineering. The cost is up there though for the level of power you get. Seeing how company is represented here (@boXem | audio), support should be easy as well.

I am happy to recommend the boXem ARTHUR 2408/N2.

EDIT: teardown is also available: https://www.audiosciencereview.com/...em-arthur-2408-n2-teardown-class-d-amp.29135/
-----------
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/
"I really like the differentiated look of the unit with custom front panel and white case which you can see better in this shot:"
Beauty is most def in the eye of the beholder. This is one of the cheesiest looking amps I've ever seen. "Custom front panel?"
 

JHC

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I for one loves the look of the Arthur, had some concern before it arrives, at the end the fit and finish was excellent.

b.jpg
 

tw99

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It's a pity that there isn't a totally black option. I can see that the technical implementation is peerless, but the colours would make it a non starter for me as I like HiFi components to be as invisible as possible.
 

pma

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Finally, here is the switching and ultrasonic performance:


boXem ARTHUR 2408 N2 Measurements FFT switching frequency Class D Stereo Amplifier.png


I checked the unit for temperature after all the test and could barely feel any rise above room temp on any of the surfaces.

@amirm, could you please tell me what was the the Y-axis calibration, i.e. "0dBrA" refers to what? I am curious because I have just measured my NC252MP module, it has switching frequency 384kHz with voltage swing of 1.02Vp-p (360mVrms). I would like to compare it with your measurement of the boXem NC122MP. Thank you.

nc252_switching_freq.JPG
 
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musicforcities

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I doubt any company these days would make a direct coupled amp. You're just asking for problems.
I believe parasound amps are exclusively Direct coupled. But they have servo offset projection and additional protection circuits to prevent damaging speakers. I believe the Schiit Vidal is also DC, but uses microprocessors to monitor for issues and protects faster than a fuse. You can have dc and ask for no problems with such advanced protection
 

musicforcities

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It never fails to amuse me when I read complaints to the effect of: "$1,200?? Robbery!! I could buy the components and the case for only $900 and assemble it myself!!"

Many of us are not hobbyists interested in soldering, screwing tiny screws and sanding off sharp edges. I'd never be able to assemble a working model at all, myself, even with excellent detailed instructions.
Indeed. If it’s a hobby, ie for fun, that’s cool and the gang. But outside of that the time i would need to assemble it would be worth more than $300 or $500 to come anywhere close to the build quality of this unit. peopke sometimes forget that labor and expertise are not free! Well done.
 

musicforcities

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Yes, it's nicer looking than 2x20 cm of ribbon cable :).
Is it also serving as a massive ground plane with perhaps a dollop of shielding for the line level? Running the line level in a single plane on a board with a huge ground plane may reduce potential noise issues a long , arching ribbon cable might be more prone to. It’s these sorts of things that matter
 

musicforcities

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It's not real powerful, but keep in mind that a lot of people have been quite happy with GFA-535s and smaller Hafler amps and they're only marginally more powerful.

It's a little pricey, but if a 60 watt (into 8 ohms) amplifier is sufficient (and in a small room with reasonable speakers, it probably is), this would seem to be a very reasonable choice.
Glad I’m not living in a flat next to your flat.

There was a time when 60 watts (not burst but maintained) was considered plenty for most medium sized rooms with reasonably efficient speakers. And it likely is more than enough if there is enough headroom. Watt is not the be all end all. I have had 30w amps that power a set of speakers better than a supposedly 100w+ amp. And yeah, one of those is a gfa 535 that is beguiling; that it is dual mono and built like a tank might help. So give me a well implemented hypex unit over a mega wattage on paper but junky amp any da

Then the wattage war started up again. I blame the rise of home theater and AVRs listing misleading wattage, subwoofer amplification specs, plus smaller less efficient speakers.

And I own at least three power amps with greater than 120wpc to well over 200wpc. I doubt I use more than 20-50w of them 90% of the time I’m a room 16x28’.
 

maty

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maty

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boXem ARTHUR 2408 N2 Teardown Class D Stereo Amplifier.jpg
 

RandomEar

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@boXem | audio I recently had an amp with a Hypex NC122MP module in house for testing. It emitted an odd hum with a bit of mains (50 Hz) mixed with three peaks at 550, 650 and 700 Hz. Wasn't very loud, but always present, as long as the SMPS was powered - also in standby. Ever noticed this with your Hypex modules? Did I just get unlucky, or is this a common thing?
 
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