AUDIOPHONICS MPA-S250NC Amp Review

[AndreaT]

On my KEF R3, will I hear significant difference between this and the $70 aiyima a07? Or some $2000 amps?

IMO yes, a resounding yes. After moving up from Sony ES to Krell KAV-300i, then to Mark Levinson ML-11, NAD S series, and finally Hypex NC400 and Nilai 500, a well recorded material, with wide dynamic variations, appropriately mastered (say Mahler’s Third by Tilson Thomas) shines more and more and conveys more of the emotional experience I enjoy when listening to BSO at Symphony Hall. A word of caution: as your reproduction achieves a better resemblance to the live performance, you get more transfixed to listening with focus on and in tune with the Music. It becomes less and less common to play music in the background while reading, texting, engaging in a conversation, performing household chores, to the displeasure of my wife.

 

[chych7]

On my KEF R3, will I hear significant difference between this and the $70 aiyima a07? Or some $2000 amps?

I have this exact Audiophonics Hypex amp from this review. Glad it gets good measurements and all, but honestly I can't really tell a difference versus my AVR's outputs (Denon X3600, which also gets good reviews here). Also A/B'd it to a cheap Fosi class D amp I have (with an instantly changing A/B switch I had built, level matched everything with a preamp on the Fosi too), barely heard a difference; very slight high frequency roll off on the Fosi. Speakers are Philharmonic BMRs. If you're spending $$ on amps, do it because there's nothing better else to spend $$ on in your system, or if you really have a high volume/power application (especially if you need to drive bass freqs).

 

[Deleted member 48726]

Pretty much all amplifiers will make a discernible noise on power up-speaker connection and power down disconnection.

With class A/AB and D the severity of the noise will depend on several factors. The largest contributor of turn on/off noise is DC offset, and with delayed connection to the speakers (relay/muting/mosfet switching), the 'pop' will be variable. DC offset varies due to ambient temperature and some designs allow for +/-150mV as a 'normal' range. Others keep to within +/-0-20mV. In other words, one day it might be a loud pop, another day silent and still be perfectly fine.

In short, the turn on/off time plot is interesting, but doesn't tell you how 'your' identical model will perform. It may have a lot more 'pop' noise or a lot less.

Yeah, I know they do but my point was more to _why_ they let this be audible on their products in contrast to most of the A/B class manufacturers.

 

[Acerun]

Man I had the complete opposite experience... Once these amps entered the Denon system everything snapped into place

 

[dweeeeb2]

So if I was to go wiim mini, minidsp flex, this amp, 2 subs and the best speakers I can afford, I’d be all set? usage: small / medium living room

 

[ralph]

I am left to wonder where exactly the low impedance protection triggers the shutdown.

Is it safe to assume that the protection will just kick in when getting "closer" to max power - like 50 % max power?

Thanks @amirm for the review and evaluating options easily available for folks in Europe.

 

[JSmith]

So if I was to go wiim mini, minidsp flex, this amp, 2 subs and the best speakers I can afford, I’d be all set? usage: small / medium living room

Most likely (speaker power requirement dependant), yes.


JSmith

 

[IamJF]

On my KEF R3, will I hear significant difference between this and the $70 aiyima a07? Or some $2000 amps?

There are not many amps on the market which are better as a Hypex module, regardless the price. Even for 20.000 or more.
If you don't hear the little humm with your speakers - you are set.

 

[Interference]

I have the XLR version, combined with a balanced-output DAC. A dead-simple source-direct clipping-free (*) setup.

(*) given the standard output levels of DACs it's very hard to bring the amp to clipping, but in general with digital attenuation and displays it's easy to control how far you are from the amp limit.

On my KEF R3, will I hear significant difference between this and the $70 aiyima a07? Or some $2000 amps?

Hard to predict. The Hypex is definitely a more capable amp but how much this will make a difference in your context it's hard to say. I would make the upgrade just for "peace of mind"

 

[Rick Sykora]

Will do. For now it is voltage.

As the Hypex NC250MP is rated for 2 ohm operation, does this mean this amp failed at 2 ohms?

Trying to understand the takeaway for these test results.

 

[pma]

As the Hypex NC250MP is rated for 2 ohm operation, does this mean this amp failed at 2 ohms?

Trying to understand the takeaway for these test results.

I will check mine in couple of hours [2ohm] and will post the result. Anyway, bridged mode worked into 4ohm, so normal mode should work into 2ohm.

Meaurements of Hypex NC252MP in bridge-tied load (BTL)

Following the discussion in the NCx500 review thread, I was curious how my PMA-NC252MP amplifier based on NC252MP module would perform in a bridged configuration. Original Hypex datasheet allows for this configuration, as we can see in the following part from the datasheet: It declares...

www.audiosciencereview.com

 

[pma]

As the Hypex NC250MP is rated for 2 ohm operation, does this mean this amp failed at 2 ohms?

Trying to understand the takeaway for these test results.

I will check mine in couple of hours [2ohm] and will post the result. Anyway, bridged mode worked into 4ohm, so normal mode should work into 2ohm.

I think I am about to confirm @amirm test results. Just measured my NC252MP implementation, which has probably the best possible cooling with large, full-size 19" - 3U aluminium box with side heatsinks. I have just made a set of measurements with 2ohm resistive load.

1. First, the noise floor with the forest of mains related lines is similar. Please take into account the graph is in dBV, so 0dBV=1V, in other words the amplitude in dB is related to 1Vrms.

... and 5W/2ohm/1kHz SINAD
.... and 5W/2ohm CCIF 18+19kHz .... 167W/2ohm/50Hz



2. Max. continuous power into 2 ohm load (but with only 1 channel driven) is 234W, then the amp protection shuts it down.

3. Below are the plots of THD and THD+N vs. power into 2ohm at 1kHz. Measuring bandwidth is a conservative 22kHz. It works well with a 2ohm resistor up to some point, like 10-20W, then the noise floor starts to have erratic behaviour and the power is limited, as shown above, to 234W with one channel driven. 5W/2ohm SINAD is 90dB. The amp does not like a complex load together with 2ohm resistive.

...... and THD+N vs. frequency into 2ohm at 168W

4. Conclusion
The amp is working well with 4-8 load, not so well with 2ohm, however usable with this load with a music signal. However, it is not the amp the could have been called "rock-steady". It is just something we call "value for money".

 

[Koeitje]

Not many speakers go to 2 ohm. If it performs well above 3 its probably fine for 99% of all speakers.

 

[Rick Sykora]

I think I am about to confirm @amirm test results. Just measured my NC252MP implementation, which has probably the best possible cooling with large, full-size 19" - 3U aluminium box with side heatsinks. I have just made a set of measurements with 2ohm resistive load.

1. First, the noise floor with the forest of mains related lines is similar. Please take into account the graph is in dBV, so 0dBV=1V, in other words the amplitude in dB is related to 1Vrms.

View attachment 290552



2. Max. continuous power into 2 ohm load (but with only 1 channel driven) is 234W, then the amp protection shuts it down.
View attachment 290555


3. Below are the plots of THD and THD+N vs. power into 2ohm at 1kHz. Measuring bandwidth is a conservative 22kHz. It works well with a 2ohm resistor up to some point, like 10-20W, then the noise floor starts to have erratic behaviour and the power is limited, as shown above, to 234W with one channel driven. 5W/2ohm SINAD is 90dB. The amp does not like a complex load together with 2ohm resistive.
View attachment 290556

...... and THD+N vs. frequency into 2ohm at 168W
View attachment 290559

4. Conclusion
The amp is working well with 4-8 load, not so well with 2ohm, however usable with this load with a music signal. However, it is not the amp the could have been called "rock-steady". It is just something we call "value for money".

I get comparable results at 2 ohms with my NC250MP. It gives up a bit sooner, but the knee is about 100 watts.

Agree that it is not bad and is better than I would have thought based on Amir's results.

 

[doug2761]

So if I was to go wiim mini, minidsp flex, this amp, 2 subs and the best speakers I can afford, I’d be all set? usage: small / medium living room

Or you could go with powered speakers like the Genelec. If I was starting over today and wanted to maximize performance then I'd probably do that. If my goal was to save money and get great results then I'd find a pair of second hand speakers and an amp like this. That's what I did. I already had the speakers and I sold my old high-dollar amp for about what I paid for it.

 

[GabrielZM]

Got this one just before the pandemics in January 2020 and very happy with it since. It is a great amplifier at bargain price and glad to see it test it and that my impressions are confirmed by numbers. Thank you amirm.

 

[MacCali]

I just thought of great rookie question, and I would assume that I am incorrect.

But which is more important less noise or distortion? I would have to guess distortion

 

[Matias]

For current hungry 2 ohms speakers it would be better to get the next up model in the MP line, the NC502MP, which is 2,5x the power for +56% the price in Audiophonics (or +30% the price in Buckeye in the US). IMO very much worth it.

 

[MacCali]

For current hungry 2 ohms speakers it would be better to get the next up model in the MP line, the NC502MP, which is 2,5x the power for +56% the price in Audiophonics (or +30% the price in Buckeye in the US). IMO very much worth it.

Does more power mean more current though?

 

[Talisman]

I just thought of great rookie question, and I would assume that I am incorrect.

But which is more important less noise or distortion? I would have to guess distortion

When you consider that many amplifiers with high levels of distortion are prized by some for their "musical" qualities, rest assured that it is much better to keep noise at bay than distortion