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Marchaudio P422 Stereo Power Amplifier Review

thin bLue

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Reviewer
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Jul 29, 2019
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Read the newly written review with the correct measured values.


"Edit : Fatal mistakes has founded.
Do not use SIANAD and Other numbers of this review.
I'll post new review and data ASAP."



This is a review and undetailed measurements of the Marchaudio P422 stereo class D power amplifier. It is on kind loan from myself and costs US $1,988.68(P422 $1,675.21 + shipping to South Korea $132.68 + import tax $180.79).

P422 is Purifi 1ET400A based amp with costom designed Power supply and buffer board

20220628_170021.jpg

Nice cushioning.

20220628_170416.jpg

Neat anodised Al body.

20220628_170456.jpg

BP feels very nice, esp. smooth-knob-like-feel of thread(but if you use this on your loudspeaker project, hole need to be sealed).
20220628_170536.jpg

but for amp? just really good at all.

20220628_170811.jpg

USB A(1 RED, 4 GND)-3.5(TIP, GND) 5V connection will work well with PC.

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100-240V 50-60Hz, without selector(full-auto-plug-n-play).

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Piezo switch

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ON

20220628_185923.jpg

Custom gain of mine.

With this newest buffer board of Marchaudio, I can get dual gain.
Marchaudio's future models will have gain selector switch outside(in my case use jumper).


Disclaimer!
I do not recommend open the chassis of Marchaudio AMPs.
It can be harmful, Danger of electric shock and burns from contact with live parts. injury from exposure to arcing, fire, and immediate expire the warranty.
20220629_035246.jpg

Well tied.
20220628_194109.jpg

Well tied too.
20220628_194124.jpg

Nice.

20220628_192455.jpg

Provided with nice looking USB, Manual inside.
(back ground is Kangaroo rather strop from Jende Industries)







Tools
20220723_204315.jpg
20220723_203856.jpg
20220723_145245.jpg
20220723_203749.jpg


20220724_012432.jpg



Disclaimer
1.Our dummy loads were not appropriate. (also, not Simulated load)
2.We didn't use any digital filters.
3.So, some of these could be trash data. careful understanding is required.

"Edit
Fatal mistake has founded.
Do not use SIANAD numbers of this review.


You can check the Voltage at oscilloscope window, 9 V
It's not an 5 W for 4 Ohm
, we pushed way more...

We used different projects with level sweeps and others(but still possibilities of same mistake has occurred...). But 5 W SINAD shows 100% wrong W, It's not 5, 10 W


I can't understand myself, how could I done this.

Still data can be used as checker for L/R uniformity. but yes otherwise we lost reliability of our data so we have to re-measure them all.

Our team is now working hard on new loads, AP's AUX-0040 filter, and proper settings.
I promise, next measurements are fully checked before posting. sorry for make massive inconvenience."



This is only one sample, does not represent the performance of all products.
4 ohm 5W bench mode 1.PNG

@4 Ohm 5 Watts @4 Ohm 10 Watts
Difference between Ch1, 2 is not amp's characteristic.
Load made noises, real SINAD is higher.

4 ohm 5W bench mode 2 (LR switch).PNG

@4 Ohm 5 Watts @4 Ohm 10 Watts
Exchanged Amp's Ch(L/R->R/L) shows same results.
The Amp does not make any significant Ch difference at all . both Ch are same
4 ohm 5W bench mode 2 (L channel best).PNG

@4 Ohm 5 Watts @4 Ohm 10 Watts
It seems P422 can rated least 105-106dB.
nice.


4 ohm 5w multi-tone test FFT.PNG

@4 Ohm 5 Watts Not sure
index.php

(https://www.audiosciencereview.com/forum/index.php?threads/topping-pa5-review-amplifier.28512/)

Multitone looks great.
well suppressed noise floor rise at high frequency.


4 ohm 5W frequency response.PNG
@4 Ohm 5 Watts Not sure
Fr : textbook-like
4 ohm 5W crosstak (R to L).PNG

@4 Ohm 5 Watts Not sure
Crosstalk soso.
but, yes it's Still OK!

2ohm level sweep.PNG

@2 Ohm but not sure about settings
It shows little instability, but some of that instabilities are caused by load(heat noise).
Still provide massive power.

index.php

(https://www.audiosciencereview.com/forum/index.php?threads/topping-pa5-review-amplifier.28512/)

4 ohm level sweep.PNG

@4 Ohm but not sure about settings
Yes, what we wanna see. even with our resistors, looks great
With proper load we would see cleaner power.



(before measurements)Meaningless subjective assessment with my own iron ears(Just cry).

It sound like crystal clear.
and I close my eyes, soon It disappears into the air feels like amp doesn't exist.

Even Otaku-music(hard to drive), it drives well.



Conclusions
1657706414.jpg


I'm happy to recommend the Marchaudio P422 Stereo Amplifier.


Reasonably priced neat Purifi based amp with nice PSU and Buffer board with RF filter for prevent IMD(Important in Class-D) Made in Australia
You can personalise the Gain of this amp when you order. it's sweet.

I learned my ignorance and importance of loads heat control ability.
And how powerful high-power amp like this.


"Edit : AMP seems nicely worked in hard conditions. But by My faults, data has no reliability.
You should not judge anything based on this review.
Our team will prepare and re-measure them all for next post. Again data of this post has non of reliability. "









Bonus


20220723_174418.jpg

E1DA Cosmos APU
USB-C powered Clean preamp with 48v Phantom power and Notch filter
Marvel of @IVX
notch 6dB 1k.PNG

Nice clean notch
1k FFT upto 1M.PNG
1k FFT upto 20k.PNG


Didn't capture 60dB gain settings, but I can confirm myself couldn't see any increase of noise floor even @ 60 dB Gain.




Conclusions
1657706414.jpg


I'm happy to recommend the E1DA Cosmos APU too.

Giant Bang for the buck.



This review is powered by 스피커 갤러리(Speakers gallery) of DC inside
 
Last edited:
From the March Audio web page for that amp: “the P422 can deliver up to 425 Watts into 4 ohms”. You measured less than half of that. On a watts per dollar basis, that isn’t terrible but not amazing either.
 
From the March Audio web page for that amp: “the P422 can deliver up to 425 Watts into 4 ohms”. You measured less than half of that. On a watts per dollar basis, that isn’t terrible but not amazing either.

His 4R test is both channels driven. The 2R test appears to be single channel driven. Where are the both channels driven numbers for 8R?

@thin bLue You need better quality resistors and you can't expect to get repeatable results with alligator clip jumpers to parallel those 4R resistors.
 
From the March Audio web page for that amp: “the P422 can deliver up to 425 Watts into 4 ohms”. You measured less than half of that. On a watts per dollar basis, that isn’t terrible but not amazing either.
Please compare the results with PA5 and AHB2.
At the THD+N 1%, you can read numbers near the rated power.
 
Thanks for sharing!

I must comment saying the Topping PA5 has no place in this review, it’s a 350$ amplifier.
 
His 4R test is both channels driven. The 2R test appears to be single channel driven. Where are the both channels driven numbers for 8R?

@thin bLue You need better quality resistors and you can't expect to get repeatable results with alligator clip jumpers to parallel those 4R resistors.
Yes, You are right. I should have use water-cooled or least better cooling performanced higher capacity resistors than this time.

100% my fault, no excuses.
 


View attachment 219982
@2 Ohm
It shows little instability, but some of that instabilities are caused by load(heat noise).
Still provide massive power.

index.php

(https://www.audiosciencereview.com/forum/index.php?threads/topping-pa5-review-amplifier.28512/)

View attachment 219981
@4 Ohm
Yes, what we wanna see. even with our resistors, looks great
With proper load we would see cleaner power.


What do the Topping PA5 plots have to do with the March Audio amplifier?
Is it a rebadged Topping or a Purifi based device?

And 1/2 the Topping amps seem like they have NO output anymore.
 
Thanks for sharing!

I must comment saying the Topping PA5 has no place in this review, it’s a 350$ amplifier.
Thanks for comment!

I'd like to remind you that the AHB2 amp is $3000.

Btw. PA5 is really high performance amp, It's really necessary to use them as fiducial for comparing amps. AHB2 too.
 
What do the Topping PA5 plots have to do with the March Audio amplifier?
Is it a rebadged Topping or a Purifi based device?

And 1/2 the Topping amps seem like they have NO output anymore.
Again, PA5 is really high performance amp, It's really necessary to use them as fiducial for comparing amps. like AHB2.

And, I can't understand what exactly "1/2 the Topping amps" means. can you explain?
 
Again, PA5 is really high performance amp, It's really necessary to use them as fiducial for comparing amps. like AHB2.

High performance compared to what?
They were the two worst amps I have even put into a system. And hissed like a Sunday morning spent at a Pentacostal revival.


They made me look around for the gawd awe full hissing, so they sounded realistically like a snakes.



And, I can't understand what exactly "1/2 the Topping amps" means. can you explain?


There are 30 pages of people generally complaining here:

Unless the MA 422 amp puffs out its smoke like a Topping, then it makes little sense to include the PA5.
or is the message that one can get the Topping for 1/6th the price?
And if it lasts 2 months, then after a year, the 6 Topping amps cost the same as MA-422?

Or what is the message we should be taking away?
 
High performance compared to what?
They were the two worst amps I have even put into a system. And hissed like a Sunday morning spent at a Pentacostal revival.


They made me look around for the gawd awe full hissing, so they sounded realistically like a snakes.





There are 30 pages of people generally complaining here:

Unless the MA 422 amp puffs out its smoke like a Topping, then it makes little sense to include the PA5.
or is the message that one can get the Topping for 1/6th the price?
And if it lasts 2 months, then after a year, the 6 Topping amps cost the same as MA-422?

Or what is the message we should be taking away?
I see, I meant PA5 under normal operating conditions. Purifi et400 has way better reliability and no-audible-hiss with normal sensitivity speakers.
I should have take more care about that point.

But, I feel some unnecessary aggressiveness in your comments. Do I just misunderstand about yor comments?

If what I felt was right, I must say we don't have to be emotional. let's solve them in developmental ways.

I'm just an idiot. I do not know so many things and I'm not professional too. so please teach me.
 
@thin bLue

I think you should consider revisiting (editing) your review with updated thd vs level results for 2,4 and 8R both channels driven when you obtain new load resistors.

The SMPS appears to be the 'new' design, so its performance under load and resultant power output achieved will be most illuminating for any potential purchasers. March Audio makes the following claims:

1658629765138.png
 
@thin bLue

I think you should consider revisiting (editing) your review with updated thd vs level results for 2,4 and 8R both channels driven when you obtain new load resistors.

The SMPS appears to be the 'new' design, so its performance under load and resultant power output achieved will be most illuminating for any potential purchasers. March Audio makes the following claims:

View attachment 220066
Strongly agree with you!


Current measurements, even with faulty load shows claimed power THD + N @ 1% point. but I think most of our community members(including myself) wanna see 'how low It can be reached, and when inflexion point starts' more accurately.

When we can get some proper tools, I'll post about new measurements ASAP.
 
It looks like March Audio’s spec is rather optimistic.
 
I see, I meant PA5 under normal operating conditions. Purifi et400 has way better reliability and no-audible-hiss with normal sensitivity speakers.
I should have take more care about that point.

To be fair, I only played the PA5 through RCAs, and the XLR performance was a 10-20dB better THD+N than the RCAs.



But, I feel some unnecessary aggressiveness in your comments. Do I just misunderstand about yor comments?
..

The only aggressiveness is in the fan-boi spruicking of the Topping products, even when they are those ones that basically suck.
So I cannot abide comparing the benchmark or the MA422 to the Topping, unless there is some explicit message about what I should be taking away as the message.
The implicit message seems to be that one can get a Top[ping for 1/6th the price.
And since it basically sucks at any price… I feel that I have to mention that as a public service announcement.



If what I felt was right, I must say we don't have to be emotional. let's solve them in developmental ways.
...

I do not see what is right about comparing the amplifier to the Topping model that basically is plagued with return complaints and reliability problems.
Even the PA5 amps that are deemed to be “working”, are gawd aweful.

But maybe the emotion is anger? as I usually go that route when people insult my intelligence, and a comparison with the Topping seems like it that sort of insult.



I'm just an idiot. I do not know so many things and I'm not professional too. so please teach me.

The rest of the review was fine… it was just the alligator clips part, and comparison with the Topping.

I suppose if you compared it with the AIYAMA A-07 then I maybe would not have commented.
It is <1/2 the price of the Topping... and it doesn’t like like a pack of vipers.


I thought that the review was pretty good, so p[lease do not take away my input as being totally critical.
It is only critical with respect to the comparison with the Topping.

Have a good day sir.
 
The only aggressiveness is in the fan-boi spruicking of the Topping products, even when they are those ones that basically suck.
Whether they do or not, your comment about reliability was out of line. OP is showing PA5 as a reference. He is doing great work in trying to review products objectively. Show some respect about that.
 
@thin bLue : According to the photos it seems you made a mistake by connecting the AP to the load contacts. It needs to be connected to the amp outputs directly, which is easy to do as your load bananas are stackable. If you measured like the photo showed then the cable from output to load ruined your measurements, as any load modulation will become exaggerated. Or in other words: you measured just the load quality. The other way (Kelvin method) would show more of the amp itself (while still needing a better load for perfect results).
 
1.Our dummy loads were not appropriate. (also, not Simulated load)
2.We didn't use any digital filters.
You put a lot of work in that review which is appreciated. Alas, unless you have an external AES-17 filter, you can't properly measure class D amplifiers. Their high frequency energy will confuse the front-end of the AP. Symptoms are its auto-gain getting confused and unreliable THD+N/SINAD. Your results don't seem to indicate these issues hit you but still, you will get push back without the external filter.

Also, your dummy loads need to have extremely low distortion of their own. Otherwise you won't able to get beyond 105 dB of SINAD or thereabouts (the actual level depends on amplifier feedback).
 
Whether they do or not, your comment about reliability was out of line. OP is showing PA5 as a reference. He is doing great work in trying to review products objectively. Show some respect about that.

I agree, it was a good review.
And I respect that.

The comparison with a Benchmark makes sense.
There is a whole thread on ASR with complaints about the PA5, so it seems like a comparison sullies his review?
(That was my main point)
 
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