boXem A 4216/E2 Stereo Amplifier Review

[mdunjic]

Between Purify, Hypex, and THX AAA, are amps pretty much a solved problem like DACs?

Definitely seems so and I couldn’t be happier. Pure undistorted sound with loads of available cleanest power for normal people prices … anyone willing to pay for ‘silky smooth sound’ (usually synonymous to pleasingly distorted) 10-100x more, be my guest, if that makes them feel special

 

[Matias]

To be honest - I am slightly disappointed, that high frequencies distortion ballooning still has not been significantly improved. This is where D Class still lags behind competent AB class amps. I was noping that increase in bandwidth would bring 10 and 15kHz lines closer to 5kHz

Optimizing for even better 1kHz SINAD is probably not worth the effort anymore.

FAQ #7.

'Class D FAQ'

Jan 20, 2021

This topic is dedicated to Frequently Asked Questions about class D amplifiers. If you have been directed here the reason is that it is easier to concentrate the frequent answers here instead of repeating them in several topics.


Q1: Class D power ratings cannot be true. How can these small and light "toy amplifiers" generate all these watts??

A1: The key word is efficiency. That means less power is wasted as heat, and as a consequence, the manufacturers don't have to attach heavy heatsinks to the amplifier and build a large chassis. But these watts and amperes are all true...

• Matias
• class d faq
• Replies: 163
• Forum: Stereo and Multichannel Amplifier Reviews

• 

 

[TurtlePaul]

First of all - finally 2nd gen Eigenfakt mesurements, in what looks like competent implementation.

To be honest - I am slightly disappointed, that high frequencies distortion ballooning still has not been significantly improved. This is where D Class still lags behind competent AB class amps. I was noping that increase in bandwidth would bring 10 and 15kHz lines closer to 5kHz

Optimizing for even better 1kHz SINAD is probably not worth the effort anymore.

10 khz THD is > 100 dB from 1.5 watts to 5 watts and >95 dB over the range. What more could you be looking for? The 15 khz line is not audible because the second harmonic is 30 khz. Hearing 20 khz, 95 dB down is also impossible (it would be interesting to see what component of the 10 khz THD is H2 and which is higher). Improving this high frequency THD is also way beyond human perception. Even much worse amps are functionally transparent.

 

[mdunjic]

10 khz THD is > 100 dB from 1.5 watts to 5 watts and >95 dB over the range. What more could you be looking for? The 15 khz line is not audible because the second harmonic is 30 khz. Hearing 20 khz, 95 dB down is also impossible (it would be interesting to see what component of the 10 khz THD is H2 and which is higher). Improving this high frequency THD is also way beyond human perception. Even much worse amps are functionally transparent.

None of the ultra high end have better high frequency distortion figures. Most of those are actually significantly worse, but they can be pleasantly distorted and people like it and think it’s high-fidelity

 

[Music1969]

@amirm: 1MHz Bandwith switching noise plot as a standard (and not only sometimes and just randomly) would be so cool!

@amirm used to always do it but now fallen off his checklist

 

[PloddyPastard]

Except for the speakers we have the same setup. Are you happy with?! For me… heaven!

Yes. I am extremely happy - enjoying it a lot!

 

[Yersinia Bestmate]

Now that's an ugly piece of gear.

Nevertheless I'd like to have one. Or two.

 

[GS430man]

Reading this review and the retirement discussion motivated me to finally create an account after many years of lurking.

Great stuff. Thank you Amir!

 

[totti1965]

Reading this review and the retirement discussion motivated me to finally create an account after many years of lurking.

Great stuff. Thank you Amir!

Welcome on board!

 

[totti1965]

Audiophonics 400 Putifi Amir measured at 109 SINAD (Low)

That’s correct!
But think:
Boxem‘s low gain is identical with audiophonics mid gain!
IMHO, a gain of 20 dB has much more usability than 12 dB:
I use my Topping B100 (with RCA Connection to the WiiM Pro Plus) in mid gain. It is 16.38 dB
For some classical pieces a bit on the week side with my 85 dB / Watt per meter speakers……
So 12 dB is simply not enough with no dedicated PreAmp - at least in most use cases.

So, apples with apples in relation of SINAD would be 105 dB (Eigentakt) vs 111 dB (Eigentakt 2 technology)

Of course all this is (100% certainly) not audible….

 

[Narrator]

I get excited by a review a few times a year, and this one is by far the most exciting of 2025!

 

[Gremlins]

I own a Benchmark AHB2 and two Fosi V3 mono’s. I can switch between them using a Luxman As-50r switching device at identical volume levels and listen to them via Revel F228-Be.
And guess what? I can’t here any difference at all..

My conclusion is this: provided good measuring linear electronic devices are used the sound is fully determined by the speakers (given a certain room).

Thanks for your return experience

What you say is a premium advice for many of us : two fosi monos brings you high fidelity in regards of power amp, paying more is only to get something looking good

 

[JSmith]

Oh no, you beat @JSmith to it! He’s loosing his edge! J/k of course.

JSmith

 

[antcollinet]

- This parameter can be clearly heard, even with ageing ears, at the difference of some other measurements.

Are you sure about that?

Our reference document suggests otherwise— and it is not as though sound from the left speaker only goes to the left ear— and vice versa.

Turntables with the single transducer pickup are terrible for crosstalk, maybe only 30dB or so separation — yet I've never heard any artefact that can be attributed to it.

I can imagine that in the artificial case when only one channel has any sound and the other is silent— then it may be possible if you listen close to the silent speaker so you can hear anything it is putting out against the much louder sound from the other.

F

'Audibility thresholds of amp and DAC measurements'

Dec 17, 2018

Introduction
A recurring theme on ASR is whether or not the various measured qualities of the devices are audible. In this post, I'll present some clear and visual thresholds for when those imperfections can be considered a potentially audible concern. I will not explain the basics of amp/DAC measurements.
Feel free to comment if you have any issues with the content of this post, be it technical, grammatical, or maybe just something that's poorly communicated.

Orange marks strict limits while green marks lenient limits.
Strict thresholds guarantee that anything...

• flipflop
• Replies: 938
• Forum: Psychoacoustics: Science of How We Hear

• 

 

[Nicolas]

Got to agree that in a future case batch, I'd like to see a full two pole power switch, even if it's on the back...

Can someone answer this numpty question please?

The ONLY Speakon connectors I've ever used, was when I was installing a Quad 707 power amp thirty odd years ago. I fumbled and faffed with them, and didn't like them at all (unfamiliarity I grant you). Imagine my surprise when Benchmark have shown how much better they can be over typical 'banana plugs!'

What's a typical gauge of cable for safely using Speakons and have the plugs improved since my iffy experiences? I think I know the answer, but many of you use these things a lot and I'd seriously appreciate the input. Thanks in advance

I am unable to definitely say if the current-gen connectors are easier to work with than 30 years ago; I have been using them for at least 25 years and don't remember having seen significant change on that front but I may be wrong.

According to the current NL2FXX spec sheet max gauge is 4mm2 (11 AWG I believe).
My own speaker cables are identical to the ones sold by Benchmark (star-quad, pair of 14 AWG conductors equivalent to one 11 AWG conductor according to the documentation) - not the easiest to assemble but not at all impossible either.
I am no expert but in general I find speakon connectors rather easy to work with, so I suspect you are right when you say unfamiliarity played a role - and perhaps the lack of readily available online documentation at the time.

 

[DanielT]

Thanks for your review Amir.

For €1,160 (USD $1,350) and then get power of 289 watts in 4 Ohm- 159 watts in 8 Ohm. Handles 2 Ohm. Good SINAD. Simply put, a superb amplifier.
If I had been in need of an amp this would have been on my list, but now I can recommend it to those looking for a really good amp.

 

[DSJR]

I was reminded of the fact that if sold through a distribution and dealer network, the price would arguably be double or more of that asked.

 

[Purité Audio]

We have Fred’s excellent Boxem products here if anyone would like to try one, ‘Arthur’ in orange is my personal favourite.
Keith

 

[grobalt]

I am no expert but in general I find speakon connectors rather easy to work with, so I suspect you are right when you say unfamiliarity played a role - and perhaps the lack of readily available online documentation at the time.

the latest generation has a nice clambing mechanism, but you need a T8 Torx. Overall way better than previous generation, i really like them

 

[Fleuch]

Everyone will have their prefer Hypex and Purifi integrator. But in the end, they all perform similarly.

My preferred is Apollon:
1) Speakon option
2) Easily accessible, user selectable gain
3) Probably the most luxurious case work on the market
4) Many configuration options
5) Dual mono option

Wondered when Apollon would be mentioned as a "runner".

The absence of a two-pole power switch, easily accessible on the front of the case, is questionable, particularly when the power supply is integral. Sometimes enthusiastic acceptance of superb measurements should not outweigh other factors, such as the positioning of controls and connections for ease of use. The slider switch appears only to place the amplifier in "stand by", leaving the power unit live.