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Impressions and internal photos of the Audiophonics MPA-S250NC

ferongr

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#1
I received my MPA-S250NC (with the RCA config, deal with it :cool:) and I took some photos of the interior. The case is 4 pieces, two identical upper and lower halves made of 4-5mm extruded aluminum with vents machined, with a nice bevel, an 8mm machined aluminum front plate and a thin steel rear plate. The top vent is towards the rear so natural convection passes airflow over the board across the length of the case. The builder has threaded the screw "rails" and used normal screws instead of self-tapping ones so the case can be assembled and disassembled with no fear of stripping.

Build seems clean with no soldering artifacts, cables are nicely routed with low level input cables separated from the high level output and main input. Resistance between the mains IEC earth pin and the amplifier's heatsink base is 0.1 Ohms so the build is properly earthed. Audio ground is separated from mains earth, the RCA and speaker connectors have insulators to prevent them from touching the case. Speaking of the speaker connectors, they are extremely high quality and grip the cables very well, as well as being easy to tighten due to the smooth threads. The IEC socket features a switch but no fuse.

Operationally, the amp is silent and doesn't buzz when the DAC connected to it is unpowered. There's no turn-on thump and an imperceptible one at turn-off. I have to put my ear 30 cm from the woofer to hear it. It seems to be driving the DBR-62s nicely and doesn't even get warm.

All in all, it seems like a good option at a bargain price for someone looking for an NC252MP amplifier at a very good price. Images are attached to this post.
 

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#2
Thanks for this impressions about the audiophonics amplifier.
Since I am also thinking to order one, can you tell me more about how it sounds?
 
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#4
Thanks for sharing. This one looks more tidy than others amps from them (via pictures on ASR). Maybe they have improved? :D
 

tmtomh

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#7
I'm seriously considering getting their HPA-S250NC - basically a dual-mono version of the above in a full-size case. Any concerns or red flags I should be aware of?
 
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ferongr

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Thread Starter #8
I've had no issue with the operation and performance of my unit. If the price and form-factor is right for you, then go for it. There don't seem to be any flaws with the build.
 
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#9
I'm seriously considering getting their HPA-S250NC - basically a dual-mono version of the above in a full-size case. Any concerns or red flags I should be aware of?
That's the one I own. Working wonderfully. I just had to dim the front led that I found too bright at night.
 
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#11
How did you dim the front led? That would be nice to do.
I had to switch it off completely.
On the wire from NC to Led there was a resistor soldered in series, I just replaced it with higher value to my liking.

Edit : photo where you can see where the resistor is, under the white heat shrink sleeve (not sure there is one on all models)

audiophonics-hpa-s250nc-stereo-class-d-amplifier-ncore-2x250w-4-ohm.jpg
 
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Xulonn

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#12
Audiophonics impresses me, and the experiences of ASR members like @ferongr reinforce my opinion. A few days ago, I inquired about a three-channel version of the below Audiophonics balanced XLR input 4-channel amp that comes with a pair of NC252MP modules. I wanted an NC252MP stereo module for L/C and a mono NC250MP substituted for the 3/4 channels to drive my center speaker, leaving one set of back panel I/O empty. And I don't want NC250MP monoblocks. This would duplicate the layout of the more expensive Nord version, although the Nord has a couple of additional features including staged startup and switchable dual XLR/RCA inputs.

Audiophonics Hypex 4-Channel Amp.jpg


Good customer service - I got a prompt reply. Unfortunately they do not do custom assembly.

Audiophonics email reply.jpg
 

CDMC

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#13
I can't believe nobody said it and I get to. Pin 1 issue. In the first amp, they have just dropped connecting Pin 1, it doesn't go to the chassis or the board. From the board, they have not chassis ground. In the second amp, they are carrying Pin 1 back to the board.
 
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ferongr

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Thread Starter #14
My amp has RCA, with an earthed enclosure, Hypex recommends separating the audio ground from mains earth, and tying the shield of the internal cable to RCA ground if not using an RC filter to connect to the case.
 

CDMC

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#15
My amp has RCA, with an earthed enclosure, Hypex recommends separating the audio ground from mains earth, and tying the shield of the internal cable to RCA ground if not using an RC filter to connect to the case.
It would help if I noticed they were RCA, not XLR. Proving once again, a little knowledge is a dangerous thing.
 

ironhorse128

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#17
I am quite happy with the amps. They sound great (of course). But not really better than the XTZ edge 300 I used before.
The problem I have is that I suddenly have a lot of electrostatic discharge when touching them or devices next to them. Maybe something else has changed, but I never noticed this before in my system. As a quick fix I connected the case of the monos to my radiator using an old speaker cable. Hope that helps.

Any thoughts on that?
 

ironhorse128

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#18
On the wire from NC to Led there was a resistor soldered in series, I just replaced it with higher value to my liking.
Thanks for the reply. I do not have a resistor in the cable to my led (see my pictures). Thus I removed one of the LED cables completely. But your dimming idea is pretty cool.
 
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#20
Thanks for the reply. I do not have a resistor in the cable to my led (see my pictures). Thus I removed one of the LED cables completely. But your dimming idea is pretty cool.
Looking at your pics, that's because they upgraded their circuit board below, I think the resistor is now a cms on it (there is none on my older circuit board). But that still allows to add a resistor on the wire to dim the led for anyone willing to.

Annotation 2020-05-13 235730.jpg
 
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