Marchaudio P422 Stereo Power Amplifier Review

[thin bLue]

@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?

I think I saw some articles about this on ASR before, so I was searching for that but I couldn't find. sorry for late response.

But, I just found some article about grounding at Marchaudio forum's technical tap.

+I think I saw connection between ground and chassis, but my memory about that is vague and I didn't left a photo. so for make sure I'll ask about this to Marchaudio!

 

[thin bLue]

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.

You are right.
(Btw, we used another 2 Ohm resistors for that. otherwise 100% correct! did you watched us while measuring? xD)

 

[Chrispy]

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.

No, that's fine, more of my point in that I don't see that March is publishing anything but perhaps a reference to the module capabilities/spec but it's simply not clear as to basis for the various specs at various impedances, which makes it hard to make comparisons to others' measurements/specs particularly for the complete amp as produced by March. The one detailed spec into 4 ohm from March is nice, but would be nicer to see more detailed specs from them.

I'm not that interested in a March amp myself, don't need one, not that interested enough to inquire.

 

[Chrispy]

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.

Yes, it's a particularly detailed spec at 100W into 4 ohm and that's the only detailed spec March is providing as a "rating" vs not providing it for the simple statements of wattage for the various 2/4/8 ohm loads. Still, if you're going to compare, its nicer to compare actual March-provided specs for their finished product and detailed ones if you're going to make detailed comparisons. Some would still find it meaningful at 400W even if they're more interested only in a 1W performance figure.

 

[Holmz]

Yes, it's a particularly detailed spec at 100W into 4 ohm and that's the only detailed spec March is providing as a "rating" vs not providing it for the simple statements of wattage for the various 2/4/8 ohm loads. Still, if you're going to compare, its nicer to compare actual March-provided specs for their finished product and detailed ones if you're going to make detailed comparisons. Some would still find it meaningful at 400W even if they're more interested only in a 1W performance figure.

Almost no one should be interested in the specs at clipping.
Maybe 100W as that is 20dB more than 1W, and would represent peeks for music with a crest factor of 20dB.
Or 100+ dB could represent 100W listening.

FCS, they provide the plot versus frequency,
The noise in micro Voltas, and a bunch of other info.
The plot goes from from milliwatts to 500W on the X-Axis.

What are you comparing the amp to? where the other amplifier provides more specs?
Please show us.

 

[Holmz]

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!

Being ~20km away, one would think so… but alas, no.


How, with your unit, do you change the gain?
Is it jumpers, or are there soldered in resistors that are put in before it shipped to you?

 

[SDC]

Being ~20km away, one would think so… but alas, no.


How, with your unit, do you change the gain?
Is it jumpers, or are there soldered in resistors that are put in before it shipped to you?

I can answer that one. It has internal jumpers. Kind of prototype, future models are told to have external switches.

 

[Holmz]

I can answer that one. It has internal jumpers. Kind of prototype, future models are told to have external switches.

And jumpers for each side, so one could biamp using a stereo amp… acting as a high-low mono block behind each speaker?

 

[Chrispy]

Almost no one should be interested in the specs at clipping.
Maybe 100W as that is 20dB more than 1W, and would represent peeks for music with a crest factor of 20dB.
Or 100+ dB could represent 100W listening.

FCS, they provide the plot versus frequency,
The noise in micro Voltas, and a bunch of other info.
The plot goes from from milliwatts to 500W on the X-Axis.

What are you comparing the amp to? where the other amplifier provides more specs?
Please show us.

My original comment was in response to rwortman's post where he was trying to compare the detailed spec via measurement from the OP vs the simplistic rating from March. I tend to agree that it doesn't make much difference at the highest levels, but that wasn't the point. I was only looking at the amp spec page from March for the P422....didn't dig for more as I would expect it to be linked to the spec page....where on the site is the further measurements/specs?

 

[SDC]

And jumpers for each side, so one could biamp using a stereo amp… acting as a high-low mono block behind each speaker?

Don't understand what you mean BTLing this amp but,

more info the OP posted before in other forum, hope it helps

 

[Holmz]

Don't understand what you mean BTLing this amp but,

more info the OP posted before in other forum, hope it helps

Bi-amping would be running a separate amp for the tweeter than the woofer.
Usually with some active crossover limiting the frequency range for each driver as in solder, wires and capacitors (etc.), or a DSP active crossover (Active-XO).

As the tweeter usually does not need a lot of power, limiting the gain to the tweeter channel is not a bad thing… and lowers the potential for hiss.

 

[thin bLue]

@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?

I got an Answer from Marchaudio.

 

[thin bLue]

No, that's fine, more of my point in that I don't see that March is publishing anything but perhaps a reference to the module capabilities/spec but it's simply not clear as to basis for the various specs at various impedances, which makes it hard to make comparisons to others' measurements/specs particularly for the complete amp as produced by March. The one detailed spec into 4 ohm from March is nice, but would be nicer to see more detailed specs from them.

I'm not that interested in a March amp myself, don't need one, not that interested enough to inquire.

Now preparing for right filter(2 months of lead time) and right load.

Ultimately, all we wanna know is real performance of complete AMP itself right? so, we can see that soon!

 

[thin bLue]

Being ~20km away, one would think so… but alas, no.


How, with your unit, do you change the gain?
Is it jumpers, or are there soldered in resistors that are put in before it shipped to you?

And jumpers for each side, so one could biamp using a stereo amp… acting as a high-low mono block behind each speaker?

As @SDC said, mine has one internal jumper and it works both channel simultaneously.
Future models are with external switch for set!

For bi-amp, use 2 stereo amp with different gain or 1 stereo amp with two mono block amps will be cool!

 

[Chrispy]

As @SDC said, mine has one internal jumper and it works both channel simultaneously.
Future models are with external switch for set!

For bi-amp, use 2 stereo amp with different gain or 1 stereo amp with two mono block amps will be cool!

With passive bi-amping why you would use amps with different gain?

 

[thin bLue]

My original comment was in response to rwortman's post where he was trying to compare the detailed spec via measurement from the OP vs the simplistic rating from March. I tend to agree that it doesn't make much difference at the highest levels, but that wasn't the point. I was only looking at the amp spec page from March for the P422....didn't dig for more as I would expect it to be linked to the spec page....where on the site is the further measurements/specs?

Latest answers from Marchaudio can help.
BTW, fortunately our B series 525 is equipped with AG52 option, so next try will be way more meaningful.

 

[SDC]

With passive bi-amping why you would use amps with different gain?

For active crossover I think he meant.

But IMO seperate amp with low gain and low watt for tweeter is better for $$$$ purpose.

 

[thin bLue]

With passive bi-amping why you would use amps with different gain?

For hybrid/active x-over applications.

 

[Chrispy]

For hybrid/active x-over applications.

The specification helps, thought you were referring to passive bi-amping as someone asked about.

 

[Chrispy]

For active crossover I think he meant.

But IMO seperate amp with low gain and low watt for tweeter is better for $$$$ purpose.

But would need same gain....