Marchaudio P422 Stereo Power Amplifier Renewed Review

[sarumbear]

Does this answer your question?

Name	THD+N (5W, 4 ohms)	SINAD (dB) (5W, 4 ohms)	Power (W) (1% THD+N, 4 ohms)	Price (USD)	Source
Benchmark AHB2 (stereo)	0.00023%	113	210	3,000	ASR
Benchmark AHB2 (mono)	0.00026%	112	500	6,000	ASR
March Audio P422	0.0006%	104	400	1,625	thin bLue

Courtesy of @Matias awesome spreadsheet.

May I ask where you get those THD+N and power values. Benchmark's spec is below and @Matias 's spreadsheet shows the same values.

CONTINUOUS AVERAGE OUTPUT POWER​

< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz

• 100 Watts per channel into 8 Ohms, both channels driven
• 130 Watts per channel into 6 Ohms, both channels driven
• 190 Watts per channel into 4 Ohms, both channels driven
• 240 Watts per channel into 3 Ohms, both channels driven
• 200 Watts into 16 Ohms, bridged mono
• 380 Watts into 8 Ohms, bridged mono
• 480 Watts into 6 Ohms, bridged mono

Benchmark AHB2 Power Amplifier

Benchmark's new AHB2 Power Amplifier - "The Quietest, Cleanest Audio Amplifier on the Planet"

benchmarkmedia.com

 

[sweetchaos]

The values are from his spreadsheet.

 

[thin bLue]

High waifu acceptance factor! People can enjoy crystal clear 2d to 3d soundstage conversion with these I bet!

Exactly!

 

[thin bLue]

Excellent! Would you say this is almost as good as the ABH2 but a lot less money?

SINAD Over 100 dB most of us can't never hear any differences between them, but more power rarely but certainly makes audible difference.

BTW, when amp turned on AHB2 consuming at least 20W, but Class-D amps have way less power consumption. It can make audible(visible) differences with our bills.

So, no additional heat and less power consumption, even with more power? I'm quite sure happier with efficient Class-D! I think It's way cooler in many ways.

 

[dtaylo1066]

Let's face it, Bruno knows his feces when it comes to Class D amp modules.

 

[thin bLue]

Let's face it, Bruno knows his feces when it comes to Class D amp modules.

Can you explain the details about that?

 

[GWolfman]

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

ROFL on the golfing pic!

 

[beefkabob]

Golfing panther. Yes, I noticed that.

 

[PeteL]

Comprehensive work as always. My only request is to abandon THD% and instead show SINAD in dB. Latter is so much easier to remember and understand.

Abandon THD%? Why? Both THD+N and SINAD are there on the dashboard no? Frankly, I think it's fair to say that a good 70% of people don't even know what a dB really mean. Everybody knows what percent mean. Plus it allow to directly compare with company specs, and to also compare a product to others that haven't been reviewed here. You want to scratch off the way audio reproduction performance have been specified for about a century?

 

[Rja4000]

After massive failure with my previous review

You overstriked the whole text, but, as far as I underdstand, only measurements are a problem.
So you might want to keep the description for reading, as an example, since it's still relevant.
Or, better even, integrate it here.

 

[Rja4000]

@thin bLue
Could you please describe your new load ?
What resistor type/values ?
How do you vary load ?
How do you cool it (if any) ?

And the same for Marchaudio's load ?
How is it different ?
(Except the fact it's fixed 4 ohm and 20W max)

I wonder what are the criteria for a good load...

I gave this kind of measurements a try, once or twice, but was never convinced with results.
I only have old amps at hand, so no comparison point, though.
So I'm interested by the learnings here.

And, maybe, we may end up with a "standard" load description for individual measurements.
Something good enough to measure up to 400W amp under 4 ohm, but with reproducible result.
Costing less than $300.
With parts that one may purchase anywhere.
(I'm ok for only one good load + a second "dirty" one, if that lowers the price. We need both channels loaded, but I may measure one and then the other,)

 

[ririt]

Promoted to home page.

As a happy P422 owner, I am glad to see such nice work promoted to home page!

 

[amirm]

I wonder what are the criteria for a good load...

Lowest load related distortion. It is called Voltage Coefficient of Resistance. The resistor modulates its value which manifests itself as distortion that is not from the amp.

 

[sarumbear]

The values are from his spreadsheet.
View attachment 230036

But where does those power values at 1% THD comes from if the manufacturer didn't supply nor @amirm measured? I re-read both reviews and cannot see it.

 

[sweetchaos]

But where does those power values at 1% THD comes from if the manufacturer didn't supply nor @amirm measured? I re-read both reviews and cannot see it.

Look at the y-axis for 1% and find the corresponding x-axis value.
So 210 watts.
Note, this looks to be approximated by Matias.

Bridge mode:

Amir shows 500 watts using the orange cursor.

In current reviews, Amir actually shows this value like this:

Looking at the left-hand side of the chart, taking the average of the left, right channels...so 81 watts.

 

[anmpr1]

For a basic 'without frills' amplifier it's very good value. Or for even less money (and less, but still a lot of, power), the P262. Five year warranty is impressive. US customers pay one hundred and thirty dollars for the company to ship it across the ocean, and that much to return it if something goes wrong. However even with that you get an attractive package for your dollar. This certainly (IMO) offers more 'bang for the buck' confidence than brands with only an Amazon (or other similar) storefront, and support policies that one often can't figure out very well. If I lived in Australia, this would surely be at the top of my short list.

 

[thin bLue]

@thin bLue
Could you please describe your new load ?
What resistor type/values ?
How do you vary load ?
How do you cool it (if any) ?

And the same for Marchaudio's load ?
How is it different ?
(Except the fact it's fixed 4 ohm and 20W max)

I wonder what are the criteria for a good load...

I gave this kind of measurements a try, once or twice, but was never convinced with results.
I only have old amps at hand, so no comparison point, though.
So I'm interested by the learnings here.

And, maybe, we may end up with a "standard" load description for individual measurements.
Something good enough to measure up to 400W amp under 4 ohm, but with reproducible result.
Costing less than $300.
With parts that one may purchase anywhere.
(I'm ok for only one good load + a second "dirty" one, if that lowers the price. We need both channels loaded, but I may measure one and then the other,)

IRH - Metal Clad Resistors from Jeil(It means No.1, Best in Korean) Electronics

IRH - Metal Clad Resistors 600W~2.8KW > Metal Clad Resistors | JEIL ELECTRONICS CO. LTD

resistors.co.kr

16 Ohm 1000 W and pararell connection to make
4 Ohm 4000 W (4 x 16 Ohm 1000 W)
2 Ohm 8000 W (8 x 16 Ohm 1000 W)

To connect them I used thick copper wires.


It has quite luxurious price tags, so you can take pararell electric grill heater resistor with water/air cooling load could be recommendable low cost option

Cooled with Air conditioner, all of 16 ohm 1000 W resistors I used was cool to touch after each drive(measurement)


with BAD loads, you can see distortions as my previous measurements.

BAD loads make louder noises and distortions than AMP so that we can't see the AMP, but only the dummy load itself.


In fact, Best loads for test the amp is simulated load(reactive) It's way harder to drive. but without accumulated various data with that specific simulated load, hard to read the meaning of the data.

 

[thin bLue]

As a happy P422 owner, I am glad to see such nice work promoted to home page!

My pleasure!

 

[Rja4000]

Lowest load related distortion. It is called Voltage Coefficient of Resistance.

I don't see that in specsheets...
???

 

[Rja4000]

Jeil(It means No.1, Best in Korean) Electronics

Unfortunately, I don't see those in Europe