boXem ARTHUR 2408/N2 Review (Stereo Amplifier)

[pma]

@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?

Maybe unlucky or something wrong with the wiring. However, these modules are not "perfect" regarding PSRR and there is no way to get rid of it. You can see it in Amir's measurements as well. But, at the level where it is inaudible.

 

[boXem]

@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?

If we talk about audible noise emitted by the amp itself, I believe you were unlucky. Never encountered such a thing, in oposition to other smpses (looking at you mean well)

 

[Sheepadoodling]

I've done a lot of research and have some basic questions about the next one up of this amp, the 3409/N2. The specs of this version is below pulled from there website. They don't really have any detailed spec sheets that I can find on their site.

Arthur 3409/N2 can deliver up to
- 250 W in 4 Ω
- 150 W in 8 Ω (34 V RMS)
- 280 W in 2 Ω (9 A RMS)
34 Volts, 09 Amperes, "3409", coincidence?
Website: https://boxem-audio.eu/en/stereo-am...k/8-body_color-textured_matte_dark_anthracite

I'm looking at 3 bookshelf speakers, listed below...

1. Polk Reserve R200
   • Website: https://www.polkaudio.com/en-us/product/bookshelf-speakers/reserve-r200
   • Spec Sheet: https://www.polkaudio.com/-/media/f...s/us/polk_reserve_bookshelf_infosheet_new.pdf
2. Klipsch RP-600M II
   • Website: https://www.klipsch.com/products/rp-600m-ii-bookshelf-speakers
   • Spec Sheet: https://d2um2qdswy1tb0.cloudfront.net/product-specsheets/RP-600M-II_Spec-Sheet_v02.pdf
3. JBL L52 (On Sale so only reason mixed with the above 2 options)
   • Website: https://www.jbl.com/bookshelf/L52.html
   • Spec Sheet: https://www.jbl.com/on/demandware.s...dfs/SC04214_JBL_L52_Classic_Spec_Sheet_HR.pdf

I heard that you need to buy an amp that has double the output of the RMS rating of the speakers in question. I've saw a review where the JBL L52 had been tested with an Emotive XPA5 amplifier, which has crazy amounts of power in the 4ohms and 8ohms category. That seems like way more than the recommended "double the output" of the speaker but that wasn't even mentioned in the review...see below link.

https://hometheaterhifi.com/reviews/speaker/bookshelf/jbl-l52-classic-bookshelf-speaker-review/

My questions concern only this model from BoXem, the 3409/N2

1. Is this amp version fine for the listed speakers?
2. Is there a specific version that pairs up nicely with this amp?
3. The JBL L52s are 4ohm speakers, but the amp can handle 2, 4, and 8, is this amp to much for these speakers since it's more than double at 75 watts of the speaker vs the 250 rating of the amp?
4. the Polk Reserve R200 can handle 2, 4, and 8 and give an RMS of 30-200w but i know from these threads their is math here in that 8 you need to cut the power output in half when going from 4 to 8, so if an amp RMS is rated at 200 @ 4ohms, then at 8 it would be 100. I guess my question is since Polk doesn't mention any difference, am I to assume it can handle 200w at 4 ohms and then 200 at 8ohms as well, just seems off or misleading or I'm just wrong and don't know and that is highly likely.
5. Continuing with the previous question, the amp, if the speaker can handle 2, 4, and 8 and the amp can do the same, which is what it states, what is the default, 2 ohms if hooked up, or 4 or 8, is there a setting somewhere I need to make to tell the amp hey, push out at 8 or 4, or does the lowest rating win out above the others? I think this was the most confusing for the Polk speakers if paired with this amp.

 

[boXem]

...

1. Is this amp version fine for the listed speakers?

Unless you listen loud high DR music in a well damped room, yes. But the speakers you listed will audibly distort well before the amp clips.

1. Is there a specific version that pairs up nicely with this amp?

Not especially. About the Klipsch, just keep in mind that Klipsch sound is not neutral at all and that they have a very high efficiency, the 2408/N2 is enough for them.

1. The JBL L52s are 4ohm speakers, but the amp can handle 2, 4, and 8, is this amp to much for these speakers since it's more than double at 75 watts of the speaker vs the 250 rating of the amp?

You will notice that speaker manufacturers never mention the impedance for amplifier rating. I always consider it is in 8 Ohm. In this case you rule applies (never heard this rule before BTW)

1. the Polk Reserve R200 can handle 2, 4, and 8 and give an RMS of 30-200w but i know from these threads their is math here in that 8 you need to cut the power output in half when going from 4 to 8, so if an amp RMS is rated at 200 @ 4ohms, then at 8 it would be 100. I guess my question is since Polk doesn't mention any difference, am I to assume it can handle 200w at 4 ohms and then 200 at 8ohms as well, just seems off or misleading or I'm just wrong and don't know and that is highly likely.

There are amplifiers allowing to adapt their output impedance, I guess this is why they list this "Amplifier Output Compatibility" at 8Ω / 6Ω / 4Ω. The 3409/N2 handles anything above 2Ω, minimum speaker impedance is 3.8Ω, so we are fine.

1. Continuing with the previous question, the amp, if the speaker can handle 2, 4, and 8 and the amp can do the same, which is what it states, what is the default, 2 ohms if hooked up, or 4 or 8, is there a setting somewhere I need to make to tell the amp hey, push out at 8 or 4, or does the lowest rating win out above the others? I think this was the most confusing for the Polk speakers if paired with this amp.

I agree that their statement is kind of misleading.
Back to basics, U = R * I, or in the case of a speaker, U = Z * I, Z being the speaker impedance changing with frequency.
The amplifier wants to apply U at a certain frequency, to be able to do this, it will need to be able to deliver I = U / Z.
This story of "Amplifier Output Compatibility" is for prehistorical gear where changing the output impedance was needed in order not to stress the poor little thing. With a modern amplifier like the 3409/N2, you do not care about this, as long as the speaker impedance is not below the minimum specified, it's working.

 

[beefkabob]

I heard that you need to buy an amp that has double the output of the RMS rating of the speakers in question. I've saw a review where the JBL L52 had been tested with an Emotive XPA5 amplifier, which has crazy amounts of power in the 4ohms and 8ohms category. That seems like way more than the recommended "double the output" of the speaker but that wasn't even mentioned in the review...see below link.

https://hometheaterhifi.com/reviews/speaker/bookshelf/jbl-l52-classic-bookshelf-speaker-review/

My questions concern only this model from BoXem, the 3409/N2

1. Is this amp version fine for the listed speakers?
2. Is there a specific version that pairs up nicely with this amp?
3. The JBL L52s are 4ohm speakers, but the amp can handle 2, 4, and 8, is this amp to much for these speakers since it's more than double at 75 watts of the speaker vs the 250 rating of the amp?
4. the Polk Reserve R200 can handle 2, 4, and 8 and give an RMS of 30-200w but i know from these threads their is math here in that 8 you need to cut the power output in half when going from 4 to 8, so if an amp RMS is rated at 200 @ 4ohms, then at 8 it would be 100. I guess my question is since Polk doesn't mention any difference, am I to assume it can handle 200w at 4 ohms and then 200 at 8ohms as well, just seems off or misleading or I'm just wrong and don't know and that is highly likely.
5. Continuing with the previous question, the amp, if the speaker can handle 2, 4, and 8 and the amp can do the same, which is what it states, what is the default, 2 ohms if hooked up, or 4 or 8, is there a setting somewhere I need to make to tell the amp hey, push out at 8 or 4, or does the lowest rating win out above the others? I think this was the most confusing for the Polk speakers if paired with this amp.

Please discard everything you've read on the internet and start over. So much of it is probably false, you're just going to confuse yourself.
You do not need an amp with double the output of the speaker rating. That's what a salesmen says to sell a more expensive amp.
1. Yes, the boxem amp will be more than fine.
2. Pairing is BS. Audio items don't pair like wine and food. If you have a well-designed amp, you're going to be fine.
3. 250 watts of amp is overkill for a 75 watt speaker, but that's not going to hurt anything but your pocketbook.
4. The amp can drive the Polk just fine.
5. You said the P word again. The amp can drive the polk just fine. Polk asks for 70 watts or more, not 250.

I don't think your speaker choices are the best. The Klipsch are especially bad. Either way, you're going to want room correction, and these will need EQ even in a perfect room. Better to get a cheaper amp and some EQ and Dirac.

But seriously, go check out some reviews HERE. Maybe at Erin's too. Start the search over.

 

[Sheepadoodling]

Please discard everything you've read on the internet and start over. So much of it is probably false, you're just going to confuse yourself.
You do not need an amp with double the output of the speaker rating. That's what a salesmen says to sell a more expensive amp.
1. Yes, the boxem amp will be more than fine.

Good to know, thanks.

2. Pairing is BS. Audio items don't pair like wine and food. If you have a well-designed amp, you're going to be fine.

I wasn't considering that audio items pair well with each other like food and wine, i was more considering the specs in how they would pair up with the amp as mentioned above that speakers can color, saturate, and change the way you hear the music

3. 250 watts of amp is overkill for a 75 watt speaker, but that's not going to hurt anything but your pocketbook.

That is good to know actually. I was wondering about that and I do realize a more powerful amp can just blow the speakers if cranked. However, I just read...oh damn, on the internet, where one could damage your amp if the speaker in question is say, out of the scope of the amps ability, either over or below the recommended specs of the amp, but as you suggested, I'll eradicate that from memory and start over.

4. The amp can drive the Polk just fine.

OK

5. You said the P word again. The amp can drive the polk just fine. Polk asks for 70 watts or more, not 250.

The .... Polk Reserve R200 stated this....where did you find the 70 watts?

Recommended Amplifier Power

30 - 200W

I don't think your speaker choices are the best. The Klipsch are especially bad. Either way, you're going to want room correction, and these will need EQ even in a perfect room. Better to get a cheaper amp and some EQ and Dirac.

But seriously, go check out some reviews HERE. Maybe at Erin's too. Start the search over.

I will start over, within reason of course, however could you provide some speaker recommendations since the 3 that I listed above seem to be distasteful in your opinion, within that price range of course....seems to be hovering around 700-800. The room is an office, about 7X10 feet, give or take a foot or so.

On a serious note, any help would be really appreciated, thanks.

 

[beefkabob]

Good to know, thanks.

I wasn't considering that audio items pair well with each other like food and wine, i was more considering the specs in how they would pair up with the amp as mentioned above that speakers can color, saturate, and change the way you hear the music

That is good to know actually. I was wondering about that and I do realize a more powerful amp can just blow the speakers if cranked. However, I just read...oh damn, on the internet, where one could damage your amp if the speaker in question is say, out of the scope of the amps ability, either over or below the recommended specs of the amp, but as you suggested, I'll eradicate that from memory and start over.

OK

The .... Polk Reserve R200 stated this....where did you find the 70 watts?

Recommended Amplifier Power

30 - 200W

I will start over, within reason of course, however could you provide some speaker recommendations since the 3 that I listed above seem to be distasteful in your opinion, within that price range of course....seems to be hovering around 700-800. The room is an office, about 7X10 feet, give or take a foot or so.

On a serious note, any help would be really appreciated, thanks.

I read the spec sheet you posted. 70 watts + for the amp.

What's your total budget for all parts? Do you have a source? Do you have EQ/room correction already? How loud are you going to listen? Plan on getting a sub?
Nothing wrong with this boxem, but you may want to go with integrated speakers. Lots of good ways to go here.

 

[Sheepadoodling]

I read the spec sheet you posted. 70 watts + for the amp.
View attachment 234036
What's your total budget for all parts? Do you have a source? Do you have EQ/room correction already? How loud are you going to listen? Plan on getting a sub?
Nothing wrong with this boxem, but you may want to go with integrated speakers. Lots of good ways to go here.

Ahh, found the specs, just going blind I suppose. I pm'd you.

 

[Willem]

Speakers make the sound. Therefore, give them the largest possible part of your budget. The Boxem is a fantastic power amplifier, but you may get better sound by spending more on the speakers, and accept a less perfect amplifier.

 

[Walter]

Speakers make the sound. Therefore, give them the largest possible part of your budget. The Boxem is a fantastic power amplifier, but you may get better sound by spending more on the speakers, and accept a less perfect amplifier.

Absolutely correct! Figure out the speakers first, then buy the best electronics you can afford with the money you have left. Sounds as if you are shooting for a total budget of $1500-$2000. Passive speakers to consider besides the Polks would be Revel M16 or M105 (should be able to get either at about 30% below MSRP from a good dealer), Wharfedale Diamond 12.2 and I'm sure several others. Actives, Kali Audio IN-5 and IN-8 come to mind, as well as Genelec 8030. You also might want to think about adding a small powered subwoofer. Room correction for sure, but that can be free except for the cost of the microphone if a computer will be your only source, which is quite likely in an office.

 

[Snoopy]

I'm more into headphones so I'm happy with my amplifier and speakers. Sure I could replace my Cambridge Cxa81 with a purifi amplifier but what that offer me with normal loudspeakers with a passive crossover?

If I ever update my stereo system I will probably go with active speakers.

Or am I wrong?

 

[AdamG]

Let’s get back to the Review. Please take sales and configuration questions/conversations to a separate thread please. Thank you for your understanding and support. Further off topic posts may be deleted without notice.

@boXem | audio any further general Amp and speaker configuration compatibility, or questions regarding other products you offer. Please respond with a link to a separate thread to take the conversation.

 

[Paffi]

It's pitty, that 2408 and 3409 are discontinued. Purifi is that much more expensive and I doubt I could hear the differences ;( Just ned a small nice looking amplifier for my ls50 metas. The boxem in white would have been optical a perfect fit.

 

[boXem]

It's pitty, that 2408 and 3409 are discontinued. Purifi is that much more expensive and I doubt I could hear the differences ;( Just ned a small nice looking amplifier for my ls50 metas. The boxem in white would have been optical a perfect fit.

I agree that a cheaper alternative to the Purifi amps is missing. But the 2408 and 3409 had very little success due to their relatively high cost (compared to the online competition) while we were not making money with them. 3409 will almost certainly come back in another, cheaper, package. Color will be any of your liking, as long as it is anthracite

 

[Paffi]

If you find some ncores in your storage, please contact me - Monos would be great. And I want THAT case (not ac cheaper one) in white/grey

 

[boXem]

Problem is not the ncores but the interface boards that we keep for servicing the amps already sold. And anyhow, what appears to be white on the pictures is indeed light grey.

 

[Martin3508]

Hello I have this amp and it is a little weak, in fact the specifications give it for 25w continuous and 125w peak but what makes the real power of an amp is what it provides continuously, right?

 

[boXem]

Hello I have this amp and it is a little weak, in fact the specifications give it for 25w continuous and 125w peak but what makes the real power of an amp is what it provides continuously, right?

Hello Martin, do you get the clipping light blinking?

 

[voodooless]

in fact the specifications give it for 25w continuous and 125w peak

Does it? Where did you find that?

 

[Martin3508]

Does it? Where did you find that?

https://www.hypex.nl/media/bb/6c/41/1646058143/NC122MP_04xx.pdf