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Marchaudio P501 Mono Block Power Amplifier Review

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don'ttrustauthority

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Small point for internal consistency .... Amir rates output as the point where distortion first rises, not at 1%.

He would possibly rate this at 80 watts at 8 ohms (he has not himself been 100% consistent with where he measures output limits, but this sharp an increase, he usually is).

That said, I disagree with his choice to do that, but I'm not the scientist.

I'm the heroin addict.
 

Matias

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> Near 1 kW of full power can be easily achieved

How long was it able to sustain this?
How long does musical signal hold at 0 dbFS?
 

TNT

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So you always measure your amps at DC?

//
 

amirm

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4. Anyone can read graph and find cut-off point they want to use. That's why I upload Data with full details not just graph. Anyway thanks for suggestions.
Well, anyone can but it is not proper to pick the top part of the clipping point and declare that as the power of the amplifier:

index.php


No one would be happy listening at that level of distortion. The amplifier is way beyond any reasonable parameter of operation once the distortion goes nearly or completely vertical.

We should also note that the AP test above only tests the amp for a short period until it captures the THD+N. This can be a fraction of a second. So you what you see is a more momentary power level than real. This is why for example amps can produce power that exceed the power supply rating. The reservoir caps produce enough power for this test but can't maintain it consistently.

So to the extent you like your measurements to be comparable to mine -- especially since you post one of mine as comparison -- fairness and proper analysis would call for applying the same metric. Or none at all. Putting the cursor at the point you did is just not proper and helps marketing messages of companies that exaggerate power levels this way.
 

amirm

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1.You can find it easily on ASR
That doesn't make it proper. if someone can give me the link and confirm this is confidential information, I will delete it.
 

restorer-john

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The amplifier is way beyond any reasonable parameter of operation once the distortion goes nearly or completely vertical.

We should also note that the AP test above only tests the amp for a short period until it captures the THD+N. This can be a fraction of a second. So you what you see is a more momentary power level than real. This is why for example amps can produce power that exceed the power supply rating. The reservoir caps produce enough power for this test but can't maintain it consistently.

So to the extent you like your measurements to be comparable to mine -- especially since you post one of mine as comparison -- fairness and proper analysis would call for applying the same metric. Or none at all. Putting the cursor at the point you did is just not proper and helps marketing messages of companies that exaggerate power levels this way.

Absolutely.

It's like advertising a roller coaster's top speed just before it flies off the track...
 

PeteL

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Well, anyone can but it is not proper to pick the top part of the clipping point and declare that as the power of the amplifier:

index.php


No one would be happy listening at that level of distortion. The amplifier is way beyond any reasonable parameter of operation once the distortion goes nearly or completely vertical.

We should also note that the AP test above only tests the amp for a short period until it captures the THD+N. This can be a fraction of a second. So you what you see is a more momentary power level than real. This is why for example amps can produce power that exceed the power supply rating. The reservoir caps produce enough power for this test but can't maintain it consistently.

So to the extent you like your measurements to be comparable to mine -- especially since you post one of mine as comparison -- fairness and proper analysis would call for applying the same metric. Or none at all. Putting the cursor at the point you did is just not proper and helps marketing messages of companies that exaggerate power levels this way.
But if the manufacturer specify the max power as 1% THD and he clearly states it, he is not exagerating power level for marketing, he is just using a different treshold that your's and there is unfortunately no firm standard but it is a common number.
Now, You are right that the amp is out of it's linear behaviour at this level, but realistically, with actual audio content, in real use even if "no one would be happy listening at that level", good news is no one ever will listen at this level continuously, it's just impossible in real life with anything else than tones, so why does it matter if it can only do it momentary, that it's because of power supply reservoir caps, the reservoir caps are part of the amp, they serve this purpose. If someone only reach 1% THD on the very loudest peaks, well the amp is specced to be able to be able to do that and the user can be totally happy letting it happen and may not hear any distortion at all.
 
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thin bLue

thin bLue

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thin bLue

thin bLue

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Outstanding. I especially appreciate the discussion of March’s implementation and how that could affect the overall performance.

Can you do an 8 ohm power sweep, please?
In fact, the lower Ohm goes down the harder to drive(drains much current).
And most of case adding ohms over 4 ohms would show quite linear power decreasing
So, About 243 W or more power is expected numbers.
(EDIT : 243 W -> 243 W @ 1%)

If I add 8 need more elbow grease, but I'll try this time.
 
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thin bLue

thin bLue

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> Near 1 kW of full power can be easily achieved

How long was it able to sustain this?
How long do you want?
Lasting 1 kW is destructive for most of residential speakers.
And I'm not sure my 8 kW load can stand linear with that lasting high power.

IMHO, 1ET7040SA has Temperature Protection so linear working duration will mostly defined by surrounding temperature.
So, I think I can't provide reliable data, due to the absence of precise constant temperature and humidity equipment and ultra-high-capacity dummy loads.
 

amirm

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But if the manufacturer specify the max power as 1% THD and he clearly states it, he is not exagerating power level for marketing, he is just using a different treshold that your's and there is unfortunately no firm standard but it is a common number.
Now, You are right that the amp is out of it's linear behaviour at this level, but realistically, with actual audio content, in real use even if "no one would be happy listening at that level", good news is no one ever will listen at this level continuously, it's just impossible in real life with anything else than tones, so why does it matter if it can only do it momentary, that it's because of power supply reservoir caps, the reservoir caps are part of the amp, they serve this purpose. If someone only reach 1% THD on the very loudest peaks, well the amp is specced to be able to be able to do that and the user can be totally happy letting it happen and may not hear any distortion at all.
You buy this amp for it ultra low distortion. If you need its peak power, then you need that clean as well. And again the point was comparison agaisnt my measurements which stop before clipping.
 

amirm

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Lasting 1 kW is destructive for most of residential speakers.
There is more chance of speaker destruction when an amp distorts. Regardless, this is not a 1 kw amplifier with that kind of measured performance.
 
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thin bLue

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Small point for internal consistency .... Amir rates output as the point where distortion first rises, not at 1%.

He would possibly rate this at 80 watts at 8 ohms (he has not himself been 100% consistent with where he measures output limits, but this sharp an increase, he usually is).

That said, I disagree with his choice to do that, but I'm not the scientist.

I'm the heroin addict.
As you already know, 1% is one of the industrial standard. so most of Amp commercials are at 1%.
(Like https://www.tpdz.net/productinfo/821195.html)

Defining the first distortion rising point is pretty dubious task. Especially when the measuring points are increased densely.

You can directly compare results with the previous my measurement and judge why I didn't mark it.
2 ohm level sweep.PNG

2 ohm level sweep large.png



Marchaudio P501 Power sweep 2 ohms.PNG


So, for consistency, rather than specifying an arbitrary inflection point, I expect it to be helpful to disclose a value for a fixed point of 0.1% , and to show an enlarged graph near the inflection points so that users can judge for themselves.

Task increases a lot, but who cares!
 

Sokel

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There is more chance of speaker destruction when an amp distorts. Regardless, this is not a 1 kw amplifier with that kind of measured performance.
It was kind of a debate about power between that and 1200as2.
If the following is correct (green line at 1Khz,4 Ohms),is that a true KW one?

1KW.PNG
 
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