Marchaudio P422 Stereo Power Amplifier Review

[thin bLue]

It looks like March Audio’s spec is rather optimistic.

For me, It seems quite fair.
but it depends on how to read that.
So, you are right too!

 

[rwortman]

For me, It seems quite fair.
but it depends on how to read that.
So, you are right too!

Well, they say 425 watts, you measure under 200. Either they aren’t being truthful or your measurement is wrong by a lot. I am guessing that they are quoting module specs and they have the modules underpowered.

 

[thin bLue]

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




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.




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.




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.

Oh, now I understand what you saying.
Failure of amps are quiet frustrating.

BTW!
Coincidentally, We have AIYAMA A07. but forgot to bring AIYAMA A07 for reference yesterday.

So, next time we might compare them in same condition!

I hope you have a great day too!

 

[Holmz]

I got the two PA5s as I was hopeful, and one AIYAMA, but returned the 2x PA5.
(For a home theatre set up.)

I’ll use something good for the L and R main speakers, but need to figure out what gains to get.
The preamp has a bypass for HT use, so it should work fine.

 

[thin bLue]

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.

Thanks for kindest words!

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).

Exactly, we had some problems with broadband measurements!
Thanks for providing critical informations about accurate measurements procedure! we could improve some next time!

 

[thin bLue]

@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).

Thanks a lot!

Amir and your comments really helpful to me.

Point the problems and providing solutions are always not easy, but you always did that for so many people. I really respect you.

I should study about that and apply the method you taught me next time!

 

[thin bLue]

Well, they say 425 watts, you measure under 200. Either they aren’t being truthful or your measurement is wrong by a lot. I am guessing that they are quoting module specs and they have the modules underpowered.

As I mentioned it's 425 W THD+N @ 1% (You can check them on Purifi's website)

THD+N @ 1% is one of the common standards.
No such a damage of truthfulness

But also most of us use much higher and tight standards.
THD+N @ 0.1% , THD+N @ 0.01% or just the point of graph starts rapid increase.

So we see the sweep data and read the graph for applying our personal standards. not only few point of number!

 

[Chrispy]

Well, they say 425 watts, you measure under 200. Either they aren’t being truthful or your measurement is wrong by a lot. I am guessing that they are quoting module specs and they have the modules underpowered.

Just visited the March site, they don't have a spec listed on the spec page other than the wattage unless you drop to this single other spec:
THD + N – 0.00019% / -114dB @ 100 Watts, 4 Ohms, 20Hz-20kHz

So at a respectable thd full band spec, it's "rated" for 100W into 4 ohm? The 425 wpc "rating" is at what thd? 1khz or full band?

 

[thin bLue]

I got the two PA5s as I was hopeful, and one AIYAMA, but returned the 2x PA5.
(For a home theatre set up.)

I’ll use something good for the L and R main speakers, but need to figure out what gains to get.
The preamp has a bypass for HT use, so it should work fine.

Can you provide sensitivity of main speakers and target loudness, and max output voltage of your preamp?

Most case about 20dB will fine for balanced connection(around 4Vrms)

 

[thin bLue]

Just visited the March site, they don't have a spec listed on the spec page other than the wattage unless you drop to this single other spec:
THD + N – 0.00019% / -114dB @ 100 Watts, 4 Ohms, 20Hz-20kHz

So at a respectable thd full band spec, it's "rated" for 100W into 4 ohm? The 425 wpc "rating" is at what thd? 1khz or full band?

How about mail directly Marchaudio?

Our job is share our 3rd party measurements so we can interpret them and make better decisions, when we buy products.

So, I'm not an insider can't provide you to proper answers for your questions. sorry for not helping.

 

[nagster]

This is a review and undetailed measurements of the Marchaudio P422 stereo class D power amplifier. It is on kind loan from 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

View attachment 219935
Nice cushioning.

View attachment 219936
Neat anodised Al body.

View attachment 219937
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).
View attachment 219969
but for amp? just really good at all.

View attachment 219938
USB A(1 RED, 4 GND)-3.5(TIP, GND) 5V connection will work well with PC.

View attachment 219939
100-240V 50-60Hz, without selector(full-auto-plug-n-play).

View attachment 219940
Piezo switch

View attachment 219941
ON

View attachment 219942
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.
View attachment 219943
Well tied.
View attachment 219944
Well tied too.
View attachment 219945
Nice.

View attachment 219946
Provided with nice looking USB, Manual inside.
(back ground is Kangaroo rather strop from Jende Industries)







Tools
View attachment 219947View attachment 219951View attachment 219953View attachment 219954

View attachment 220001


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.

This is only one sample, does not represent the performance of all products.
View attachment 219974
@4 Ohm 5 Watts
Difference between Ch1, 2 is not amp's characteristic.
Load made noises, real SINAD is higher.
View attachment 219975
@4 Ohm 5 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
View attachment 219976
@4 Ohm 5 Watts
It seems P422 can rated least 105-106dB.
nice.


View attachment 219977
@4 Ohm 5 Watts

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

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


View attachment 219980@4 Ohm 5 Watts
Fr : textbook-like
View attachment 219978
@4 Ohm 5 Watts
Crosstalk soso.
but, yes it's Still OK!

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

(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.



(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
View attachment 219987

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.











Bonus


View attachment 219983
E1DA Cosmos APU
USB-C powered Clean preamp with 48v Phantom power and Notch filter
Marvel of @IVX
View attachment 219984
Nice clean notch
View attachment 219985View attachment 219986

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




Conclusions
View attachment 219987

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

Experts have already posted it, but I will also post it. (Especially when publishing measured values.)
For speaker amplifiers,
Eliminate the alligator clip from the load resistance line. (Preferably also from the measurement line)
Branch the wire in the load resistance direction and the measuring instrument direction at the output terminal of the amplifier. Eliminate the common conductor between the load resistance direction and the measuring instrument direction.
Distortion and noise can increase if the load resistance is not of high quality, but it is helpful if their absolute values are not important. (gain, FR, clipping point, etc.)
When measuring the audible band of a Class D amplifier, before inputting the output signal to the measuring instrument, pass it through a passive filter to sufficiently attenuate the carrier wave. (At least for AP)
go for it.

 

[thin bLue]

Experts have already posted it, but I will also post it. (Especially when publishing measured values.)
For speaker amplifiers,
Eliminate the alligator clip from the load resistance line. (Preferably also from the measurement line)
Branch the wire in the load resistance direction and the measuring instrument direction at the output terminal of the amplifier. Eliminate the common conductor between the load resistance direction and the measuring instrument direction.
Distortion and noise can increase if the load resistance is not of high quality, but it is helpful if their absolute values are not important. (gain, FR, clipping point, etc.)
When measuring the audible band of a Class D amplifier, before inputting the output signal to the measuring instrument, pass it through a passive filter to sufficiently attenuate the carrier wave. (At least for AP)
go for it.

Thanks fo feedback and summary!

It helps a lot!

 

[Holmz]

Can you provide sensitivity of main speakers and target loudness, and max output voltage of your preamp?

Most case about 20dB will fine for balanced connection(around 4Vrms)

Yeah - 84dB speakers.
My preamp does 1v out of RCAs, and it has a +12dB boost if I need it.

And I am thinking 90 dB(A) RMS with 100+dB SPL peaks for the loud parts.


I have not hooked up the AVP/AVR yet, but it has balanced outputs and on the preamp, when the AVP goes in, there is a bypass so I do not need the preamp one to bypass the AVR to the amps.

Therefore I was going to use less gain on the amp, sort of like what it looks you got from Alan.

The preamp usually suits around -30dB for music so less amp gain means I would just twist the knob a bit more.

With the Topping PA5 I needed its volume so low to avoid the hissing, that I then needed to run the preamp flat out to get any sound out.

 

[Holmz]

Just visited the March site, they don't have a spec listed on the spec page other than the wattage unless you drop to this single other spec:
THD + N – 0.00019% / -114dB @ 100 Watts, 4 Ohms, 20Hz-20kHz

So at a respectable thd full band spec, it's "rated" for 100W into 4 ohm? The 425 wpc "rating" is at what thd? 1khz or full band?

I think that the 100W is the spec for where the THD is rated.

The 425W is at 4ohms, and the THD is sort of meaningless at 400W, compared to say at 1W RMS.

He also gives the noise as 18 microvolts.

 

[pjug]

As I mentioned it's 425 W THD+N @ 1% (You can check them on Purifi's website)

THD+N @ 1% is one of the common standards.
No such a damage of truthfulness

But also most of us use much higher and tight standards.
THD+N @ 0.1% , THD+N @ 0.01% or just the point of graph starts rapid increase.

So we see the sweep data and read the graph for applying our personal standards. not only few point of number!

But your 4 ohm curve falls way short of what the 1ET400A data sheet shows, no matter how you want to spec it (@rwortman 's point, I thought). Or do I misunderstand something?

 

[restorer-john]

@thin bLue

I notice your photographs show a three pin IEC chassis socket. I also see only an active and neutral (blue/brown) incoming pair to the SMPS. Is the IEC earth pin connected to the chassis as it should be if such a socket is fitted? What AC cable did March supply with the product?

 

[thin bLue]

Yeah - 84dB speakers.
My preamp does 1v out of RCAs, and it has a +12dB boost if I need it.

And I am thinking 90 dB(A) RMS with 100+dB SPL peaks for the loud parts.


I have not hooked up the AVP/AVR yet, but it has balanced outputs and on the preamp, when the AVP goes in, there is a bypass so I do not need the preamp one to bypass the AVR to the amps.

Therefore I was going to use less gain on the amp, sort of like what it looks you got from Alan.

The preamp usually suits around -30dB for music so less amp gain means I would just twist the knob a bit more.

With the Topping PA5 I needed its volume so low to avoid the hissing, that I then needed to run the preamp flat out to get any sound out.

It sounds, same gain settings with mine would work! (Are your speakers 4 Ohm and listening at about 2 m distance? then It'll fit for you)

You can directly contact Marchaudio to ask about configure the gain settings!

 

[thin bLue]

But your 4 ohm curve falls way short of what the 1ET400A data sheet shows, no matter how you want to spec it (@rwortman 's point, I thought). Or do I misunderstand something?

I mentioned about that at disclaimer.

In this measurements, P422 amp drived really well even with not suitable loads(not well coold and low heat capacity)

the Sweep shows how much THD+N @ certain wattage. but this time we measured THD+N from "load" + "AMP" not exactly AMP itself.

But, I can't deny I confused you and other members with incomplete measurements. I apologise for that.

 

[restorer-john]

But your 4 ohm curve falls way short of what the 1ET400A data sheet shows, no matter how you want to spec it (@rwortman 's point, I thought). Or do I misunderstand something?

It does fall way short on his both channels driven in 4R plot, but I think we should wait until he retests with new resistors. If you notice the picture of his 'setup', he has 2x8R and 1x4R resistors. So he must have paralleled the two 8R to get 4R and used all three for the both channels driven in 4R. Then he paralleled again to get the single channel into 2R.

Unless the amplifier is grossly over specified, I think he may have read off the results for two 8R resistors? Whatever, he needs to revisit the tests before proclaiming the amplifier doesn't meet specs.

 

[pjug]

I think he may have read off the results for two 8R resistors?

I does look like the 8R power curve.