Impressions and internal photos of the Audiophonics MPA-S250NC

[Ykar]

Is there a way you could take a closer photo of the board in the yellow circle area please ? They did something to the input signal here, I'd like to understand what is that. Left is Chan1, right is Chan2 when used with Stereo NC models.
This looks like 10Ko or 2Ko to ground for each Hot and Cold but not sure.

 

[ironhorse128]

Is there a way you could take a closer photo of the board in the yellow circle area please ? They did something to the input signal here, I'd like to understand what is that. Left is Chan1, right is Chan2 when used with Stereo NC models.
This looks like 10Ko or 2Ko to ground for each Hot and Cold but not sure.

I have this picture (of one of my monos). Does it help?

But I would not have a problem to open it up again.

 

[Ykar]

Perfect thanks, so that's 10Ko to ground for each hot and cold input pin. I will need to figure out why they added that for. Maybe some sort of basic input filter.

 

[ironhorse128]

I changed the standard silver front screws of my AUDIOPHONICS monos to black screws.
I think it looks awesome.
I bought these screws https://www.ebay.de/itm/113235755220 in size M4 x 10mm. They fit perfectly.

 

[tmtomh]

Am I crazy, or was there a photo in this thread or another audiophonics thread of the inside of one of their units with a switch that enabled dimming or turning-off of the LED without having to disconnect it or solder in a resistor? I just got one of their units and I while it's literally the first couple of hours, I'm liking it a lot - but that LED is a bit bright.

 

[Ykar]

You probably have seen that on Ghentaudio builds, I'm quite sure there no such a switch on Audiophonics builds

 

[ironhorse128]

You most certainly have to solder, which is actually not such a big deal.

 

[Nathan_A]

Am I crazy, or was there a photo in this thread or another audiophonics thread of the inside of one of their units with a switch that enabled dimming or turning-off of the LED without having to disconnect it or solder in a resistor? I just got one of their units and I while it's literally the first couple of hours, I'm liking it a lot - but that LED is a bit bright.

I realize this is going to sound hokey, but on every single thing I own that has an LED that's waaaaaay too bright, I use black Sharpie to color whatever plastic surface/lens the light comes through. It's effective, you can make it not even noticable, and you can trivially remove it with a little alcohol on a cotton swab if you ever want/need to.

 

[ironhorse128]

I realize this is going to sound hokey, but on every single thing I own that has an LED that's waaaaaay too bright, I use black Sharpie to color whatever plastic surface/lens the light comes through. It's effective, you can make it not even noticable, and you can trivially remove it with a little alcohol on a cotton swab if you ever want/need to.

I like my panels to be completely black.

 

[Koeitje]

You probably have seen that on Ghentaudio builds, I'm quite sure there no such a switch on Audiophonics builds

Standard Hypex NC400 kits also have 3 led option: off, on, bright.

 

[daftcombo]

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.

Though I like Audiophonics amps, I don't have the same experience.
The units I have buzz a bit (not in the speakers, I mean the units themselves) when connected to the power outlet (even on sleep mode), and do get warm.
I have a MPA-S252NC and a HPA-S500NC.
Still I would buy again as those are great products for the price.

 

[ironhorse128]

Though I like Audiophonics amps, I don't have the same experience.
The units I have buzz a bit (not in the speakers, I mean the units themselves) when connected to the power outlet (even on sleep mode), and do get warm.
I have a MPA-S252NC and a HPA-S500NC.
Still I would buy again as those are great products for the price.

I also have this buzz from the unit itself. But it is so quite and it is actually not audible at 30 cm distance. Thus, this is an non-issue for me. I am very happy that I have zero noise floor from my speakers and no pop at on/off.

 

[ririt]

Though I like Audiophonics amps, I don't have the same experience.
The units I have buzz a bit (not in the speakers, I mean the units themselves) when connected to the power outlet (even on sleep mode), and do get warm.
I have a MPA-S252NC and a HPA-S500NC.
Still I would buy again as those are great products for the price.

Though I like Audiophonics amps, I don't have the same experience.
The units I have buzz a bit (not in the speakers, I mean the units themselves) when connected to the power outlet (even on sleep mode), and do get warm.
I have a MPA-S252NC and a HPA-S500NC.
Still I would buy again as those are great products for the price.

since you have the 2 models, I am curious to have your feedback on the following: I will use a stereo purifi amp to power my left and right channels in a Hifi/HC setup. To power the Central channel I am hesitating between a mono NC250 or NC400 or NC500. What would be your advice?
thanks in advance for your feedback

 

[daftcombo]

since you have the 2 models, I am curious to have your feedback on the following: I will use a stereo purifi amp to power my left and right channels in a Hifi/HC setup. To power the Central channel I am hesitating between a mono NC250 or NC400 or NC500. What would be your advice?
thanks in advance for your feedback

Can you give more details about the speaker you plan to feed?

Both my amps feed a pair of Focal Aria 906, and the S252NC is already sufficient. I bought the S500NC for my living-room just because it would look better than a smaller unit on my shelf, and also because if Amir's measurements of the Aria 906 show a headless panther, I'll probably have to purchase new speakers.

 

[ironhorse128]

I bet the Aria 906 will measure very well.

 

[tmtomh]

I realize this is going to sound hokey, but on every single thing I own that has an LED that's waaaaaay too bright, I use black Sharpie to color whatever plastic surface/lens the light comes through. It's effective, you can make it not even noticable, and you can trivially remove it with a little alcohol on a cotton swab if you ever want/need to.

Not hokey at all - as I was falling asleep last night I thought, "What if I just used a Sharpie?" I wasn't sure how well it would work, though - specifically how even the blacking-out would look and whether it would be removable later. So I appreciate your report! I'll probably try it.

You probably have seen that on Ghentaudio builds, I'm quite sure there no such a switch on Audiophonics builds

Ah, that must have been it - explains why my searches turned up nothing. Many thanks!

Though I like Audiophonics amps, I don't have the same experience.
The units I have buzz a bit (not in the speakers, I mean the units themselves) when connected to the power outlet (even on sleep mode), and do get warm. I have a MPA-S252NC and a HPA-S500NC. Still I would buy again as those are great products for the price.

I also have this buzz from the unit itself. But it is so quite and it is actually not audible at 30 cm distance. Thus, this is an non-issue for me. I am very happy that I have zero noise floor from my speakers and no pop at on/off.

I don't hear any buzzing on mine. However, I have my unit connected to a DC blocker - I had to get one because my prior amp has a giant toroidal transformer that would quietly but audibly buzz, no doubt from dirty AC on my local municipal grid.

From what I've read, toroidals are more susceptible to buzzing than conventional transformers, and the transformers in the Class D amps aren't terribly large, so it's possible the mechanical buzzing you're hearing could be from something else. But the fact that the sound is not very loud, can't be heard from far away, is not coming through the speakers, and apparently is not experienced by most folks, suggests to me that DC in your AC feed might be the culprit.

 

[ririt]

Can you give more details about the speaker you plan to feed?

I want to feed 3 Dali Rubicon LCR (impedance 4 ohms, yield 89dB)

 

[bilzebubba]

I want to feed 3 Dali Rubicon LCR (impedance 4 ohms, yield 89dB)

What a coincidence! I too am wondering if the S252NC is enough, and I want to feed either the Dali Mentor Menuet (6 ohms I think, and 86db) or swap out my ancient Quad 405-II to those speakers and drive a pair of Paradigm Prestige (6/86 again), both of which sound like absolute garbage driven by my not-all-that-cheap NAD D3045 (unspecified Hypex, 60w/8and4Ohms both), but which sound absolutely fine with the Quad, so I thought of using the NAD as a Dac/pre only, but still on the fence about going all the way to a Purifi amp or S252NC or whatnot... I expect I'll jump off the fence soon enough, but which way? (@MarchAudio very helpfully assured me that the S252NC technically was enough, but is it enough for that irrational part of my brain that wants to buy the Purifi anyway though I can't afford it yet?) Haha

 

[ririt]

What a coincidence! I too am wondering if the S252NC is enough, and I want to feed either the Dali Mentor Menuet (6 ohms I think, and 86db) or swap out my ancient Quad 405-II to those speakers and drive a pair of Paradigm Prestige (6/86 again), both of which sound like absolute garbage driven by my not-all-that-cheap NAD D3045 (unspecified Hypex, 60w/8and4Ohms both), but which sound absolutely fine with the Quad, so I thought of using the NAD as a Dac/pre only, but still on the fence about going all the way to a Purifi amp or S252NC or whatnot

I did some calculation using various guidelines found on the web (especially this one http://alkasar.online.fr/audio/dimensionner_ampli.html but it is in french!). It leads to the need of a power of 140 watts to feed the Rubicon LCR and be able to reach 85dB at listening position (THX standard). Such calculation includes a crest factor of 16 and a listening position at 3 meters from loudspeakers. Using your parameters (6 ohms / 86dB), same caculation gave me 190 watts for your speakers. That may explain why your QUAD (100 watts under 8 ohms) sounded much better that your NAD . Looking at the specs of the Purifi and the S252NC, both can do the job! Better specs with the purifi but much higher price... Audiophonics in France wrote me that the Purifi was more musical than the Hypex which correlates what stated on this forum by March Audio.
Hope that will help you....

 

[bilzebubba]

I did some calculation using various guidelines found on the web (especially this one http://alkasar.online.fr/audio/dimensionner_ampli.html but it is in french!). It leads to the need of a power of 140 watts to feed the Rubicon LCR and be able to reach 85dB at listening position (THX standard). Such calculation includes a crest factor of 16 and a listening position at 3 meters from loudspeakers. Using your parameters (6 ohms / 86dB), same caculation gave me 190 watts for your speakers. That may explain why your QUAD (100 watts under 8 ohms) sounded much better that your NAD . Looking at the specs of the Purifi and the S252NC, both can do the job! Better specs with the purifi but much higher price... Audiophonics in France wrote me that the Purifi was more musical than the Hypex which correlates what stated on this forum by March Audio.
Hope that will help you....

Thanks so much! I had just edited my post to include the info that March Audio was so kind to give me, but you answered just as I saved...I will go back to that site and input for a much larger distance, then, as this particular setup is in a combo office/living room that is about 30 feet long!