• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). There are daily reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

boXem ARTHUR 2408/N2 Teardown (Class D Amp)

Helicopter

Major Contributor
Joined
Aug 13, 2020
Messages
2,684
Likes
3,889
Location
Michigan
One other good reason to use a PCB to bridge from the ribbon cable is strain relief. Despite improvements when using the Ghent connector, twisted-pair (tp) cables (like Mogami wire) place more force on the ribbon cable connector. This is why you see some implementations taping the connector in place. I suspect a volume producer would hot glue or use something to retain the connector.

Despite the apparent robustness of tp wiring, my experience after building several Hypex amps is that the heavier wire can pull the connector away from the header. Without strain relief, the result is marginal connection that can reduce output and/or introduce hum.

For my next builds, I plan to use the eval board as it adapts the ribbon cable connections to input connectors with locking retention. So, even without needing to repurpose a one case for different size modules, Boxem‘s PCB provides a better system solution in my experience. :cool:
Yeah those ribbon connector receptacles suck. I have mine so the input stays put on the shelf, but it will probably get the intermittent fault back the instant I move it from its current location. I am thinking about soldering the wires right to the pins like I did when I installed the digital output mod on @BDWoody 's 'Wandering Puffin.' It would be a bit less modular, but it sure would stay connected. The Boxem board seems like a smart and sensible solution.
 

boXem

Major Contributor
Manufacturer
Joined
Jun 19, 2019
Messages
1,628
Likes
3,563
Location
Europe
Looks like some (a lot?) people are confused by what the black fluffy thingie (TM) around the IEC socket. Is it hiding something like a filter or a secret module? If there is nothing to hide, why is it there?
The answer is that the IEC socket looks like this without the black fluffy thingie (TM):
1640189326342.png

As can be seen, there are metal parts. And these metal parts can be live pending connection to mains and rocker switch position. Without the black fluffy thingie (TM) idiots like myself tend to be electrocuted when they do not pay attention to where they put their fingers.
 

Madjalapeno

Senior Member
Forum Donor
Joined
Aug 13, 2021
Messages
453
Likes
1,073
Location
NH, USA

norcalscott

Active Member
Forum Donor
Joined
Oct 30, 2020
Messages
180
Likes
275
Location
Sierra Foothills
Looks like some (a lot?) people are confused by what the black fluffy thingie (TM) around the IEC socket. Is it hiding something like a filter or a secret module? If there is nothing to hide, why is it there?
The answer is that the IEC socket looks like this without the black fluffy thingie (TM):

As can be seen, there are metal parts. And these metal parts can be live pending connection to mains and rocker switch position. Without the black fluffy thingie (TM) idiots like myself tend to be electrocuted when they do not pay attention to where they put their fingers.

Is there a user replaceable fuse on the amplifier board? I've seen these IEC sockets with fuses but it doesn't look like this one has a fuse? Not meaning to be critical, just curious - this is a very clean build.
 

boXem

Major Contributor
Manufacturer
Joined
Jun 19, 2019
Messages
1,628
Likes
3,563
Location
Europe
Is there a user replaceable fuse on the amplifier board? I've seen these IEC sockets with fuses but it doesn't look like this one has a fuse? Not meaning to be critical, just curious - this is a very clean build.
The fuse is not user replaceable. This fuse is installed as a last barrier in the case when the SMPS safety mechanisms would not operate. Said differently, if the fuse is open, that means that the SMPS went bersek and is destroyed. So it is not only the fuse that would need replacement but the entire board.
 

EJ3

Major Contributor
Forum Donor
Joined
Dec 10, 2019
Messages
1,465
Likes
1,114
Location
James Island, SC
Very nice. Theoretically it could be half the size.
Then if it is kept hot (as my mother keeps our home at 26 degrees or higher) then there is little leeway for for heat dissipation.
I'll buy a bigger than necessary box that has better heat dissipation abilities every time. The annual average outside high for the day is 30 & the annual average outside low for the day is 27. So it is never cool here but much of the time our door & windows are open. Electronics need to be able to dissipate their heat or they soon die in our climate (Saipan).
 

Digital Mastering System

Active Member
Joined
Jan 3, 2020
Messages
135
Likes
160
Location
MN
Valuable transistors are the last line of defense for the precious fuses!
 

RandomEar

Active Member
Joined
Feb 14, 2022
Messages
212
Likes
426
I've looked in the review thread and here, but didn't see any indication: Can the auto on/off be deactivated? Maybe using an internal jumper?
 

RandomEar

Active Member
Joined
Feb 14, 2022
Messages
212
Likes
426
Nope. Out of curiosity, why would you want to disable it?
As far as I understand, it takes a second or two for the amp to switch on from standby/auto off, right? In any case, it's not instantaneous. I'm thinking that this could potentially be annoying in some scenarios where I occasionally have some audio on and longer pauses in-between: e.g. reading something, then switching back to music or a youtube video. In that case, the first seconds of the audio would always be cut off and I would have to restart it. In this scenario, which is pretty common for my usage, I might prefer to deactivate the auto on/off and just live with the higher idle power draw. For the NCore modules, that is pretty low already.

I think the auto on/off is pretty cool and certainly unique amongst NCore implementations. Nonetheless, making it configurable would be a plus for me :)
 

boXem

Major Contributor
Manufacturer
Joined
Jun 19, 2019
Messages
1,628
Likes
3,563
Location
Europe
As far as I understand, it takes a second or two for the amp to switch on from standby/auto off, right? In any case, it's not instantaneous. I'm thinking that this could potentially be annoying in some scenarios where I occasionally have some audio on and longer pauses in-between: e.g. reading something, then switching back to music or a youtube video. In that case, the first seconds of the audio would always be cut off and I would have to restart it. In this scenario, which is pretty common for my usage, I might prefer to deactivate the auto on/off and just live with the higher idle power draw. For the NCore modules, that is pretty low already.

I think the auto on/off is pretty cool and certainly unique amongst NCore implementations. Nonetheless, making it configurable would be a plus for me :)
Understood. Thanks for your feedback!
 

EJ3

Major Contributor
Forum Donor
Joined
Dec 10, 2019
Messages
1,465
Likes
1,114
Location
James Island, SC
Understood. Thanks for your feedback!
For me, the fact that it has auto on/off (as well as a form factor that is not insanely tight) are reasons that I am considering this amp over almost all others. Unfortunately, renovating a house that my wife & I just bought to a livable standard (as well as moving from the Island of Guam to an Island off of Charleston, South Carolina (USA) (where I grew up) and all that entails, has prevented me from already having 1 of these.
 
Last edited:
Top Bottom