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March Audio P122 Class D Amplifier Measurements

amirm

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#1
This is a write-up and detailed measurements of the March Audio P122 class D Hypex based stereo power amplifier. It was sent to me by the company (@March Audio). The P122 costs US $750.

Due to my relationship with company owner, I won't be performing a review or providing a recommendation one way or the other. So don't look for panthers on pictures either.

The P122 uses similar packaging to the rest of March Audio products:

March Audio P122 Hypex Class D Stereo Amplifier Audio Review.jpg

There is just a touch button that turns the unit on and off (really on and standby).

The back panel has very nice and really long speaker terminals:

March Audio P122 Hypex Class D Stereo Amplifier Back Panel Speaker Connectors Audio Review.jpg

In use, the P122 never complained or get warm. It passed all the tests without going into protection mode.

Power supply is switching as noted on the unit so works as is worldwide.

Amplifier Audio Measurements
As usual we start with our dashboard of 1 kHz tone into 4 ohm load:

March Audio P122 Hypex Class D Stereo Amplifier Audio Measurements.png


As noted on the THD+N panel, performance is roughly the same as the spec in one channel and slightly better in the other. Distortion and noise combined is near top of class:

1583040594869.png


Signal to noise ratio is excellent:

March Audio P122 Hypex Class D Stereo Amplifier SNR Audio Measurements.png


Crosstalk is respectable as well:
March Audio P122 Hypex Class D Stereo Amplifier Warm up Audio Measurements.png


Frequency response is good but not flat out to infinity as some amps are:
March Audio P122 Hypex Class D Stereo Amplifier Frequency Response Audio Measurements.png


Multitone test shows a few odd spikes in mid frequencies:

March Audio P122 Hypex Class D Stereo Amplifier Multitone Audio Measurements.png


But levels are nearly 100 dB down so not a cause for concern.

Amplifier Power Measurements
Let's start with 4 ohm:
March Audio P122 Hypex Class D Stereo Amplifier Power into 4 Ohm Audio Measurements.png


We are a bit shy of the specification on power but distortion and noise is much better than typical mass market product. Same is true of 8 ohm load:

March Audio P122 Hypex Class D Stereo Amplifier Power into 8 Ohm Audio Measurements.png


Not sure what explains the shortfall in power.

These amplifiers have regulated switching power supplies so usually don't produce more power than continuous:
March Audio P122 Hypex Class D Stereo Amplifier Power into 4 Ohm Max and Burst Audio Measureme...png


Conclusions
While the power level is on the low side, the performance is much better than typical brand name amplifiers.

------------
As always, questions, comments, recommendations, etc. are welcome.

Amazing things you learn. Apparently there is a Figurine Panther conference in Las Vegas! Naturally the panthers are pounding on me to take them there. I called the airline and they said they cannot go as luggage and I have to buy them all separate tickers. So please donate everything you can so I can send them on this trip using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

RayDunzl

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#2
It didn't get a Panther?

Oh.

Nevermind.

(that's what I get for just looking at all the pretty pictures)
 
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Sal1950

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#5
Hoping to hear from the manufacturer explaining the shortfall in power.
I'm disappointed in these numbers, expecting honest ratings from him? :(
 

astr0b0y

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#6
Maybe the 120V US power system somehow reduces the amps output power? I know this is probably a silly idea, but the power drop is fairly linear.
Personally I don't understand the appeal of power amps less than 200W into 8ohm.
 
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amirm

amirm

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Thread Starter #7
Just looked up Hypex P122MP module:
1583044966720.png


Power is rated at 1% THD+N which is higher than what I allow in my sweep graphs. But it is what I got at 1%:

 

March Audio

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#8
Hoping to hear from the manufacturer explaining the shortfall in power.
I'm disappointed in these numbers, expecting honest ratings from him? :(
Hi Sal

As Amir explained above he takes his measurement point at a lower distortion level than Hypex. 1% is a very typical level for manufacturers to quote, although we have had some debate about whether it is the most appropriate level to use and what otherwise is. Basically Amirs measurements are right in line with Hypex specs. For reference 0.001% is -100dB.

1583049868126.png


Thanks @amirm for the test data :)


...and before anybody asks, yes the left and right labelling is now swapped over to the convention :)
 
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#10
Another Ncore that performs very good !

This is the NC122MP module inside ?

I have one in test an I think ths is the best amp I "build" (this WIY not DIY...)
 

digicidal

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#13
The panthers gives a size reference of the device. Now we have no clue how large this amp is physically.
A neutral panther maybe for ”non review”-reviews?
From the product page unless @March Audio has changed something:
Dimensions 330mm x 180mm x 75mm

I don't know the dimensions of the panthers... so I'd prefer measurements. ;)
 
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#14
Hoping to hear from the manufacturer explaining the shortfall in power.
I'm disappointed in these numbers, expecting honest ratings from him? :(
Don't worry this module is capable of driving difficult speaker, tested on Focus Audio FS 68 (not very easy to drive even if this is a bookshelf)
 

March Audio

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#15
Don't worry this module is capable of driving difficult speaker, tested on Focus Audio FS 68 (not very easy to drive even if this is a bookshelf)
Yes they can handle below 2 ohm loads and deliver 12.5 amps. The power is enough for many people.
 

March Audio

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#17
So we have again quite a big difference between channels, in spuriae spectral lines, probably due to internal wiring scheme, or module PSU proximity.

View attachment 52306

If you look closely at the spec sheet you will find one channel is actually performing better than spec. The other is in line with spec. Just the nature of the modules and their layout. They do have a degree of variation which is not audible.

At Pr/2 (60 watts) , the typical figure is stated as 0.0015% (96.5dB) and max as 0.0024% (92.5dB). My testing has shown they are consistly around the typical value.
 
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deafenears

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#18
mains 60Hz + harmonics / spuria still present here in this unit like with the P502 unit measured?

EDIT: Ah, went back through the P502 thread and appears to be measurement setup related.
 

March Audio

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#19
mains 60Hz + harmonics / spuria still present here in this unit like with the P502 unit measured?

EDIT: Ah, went back through the P502 thread and appears to be measurement setup related.
Yes, I will send in another P502 soon for re-test.
 
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