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Marchaudio P501 Mono Block Power Amplifier Review

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JasonWells

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Would you agree that if someone was interested in this amp, they should think twice about purchasing it from someone who creates puppet accounts to defend it and refuses to acknowledge when asked if he is him per above? I am asking hypothetically ;).
Amir, I am not Alan. the technical facts are the technical facts. I have not mentioned March Audios p501. this has been entirely about the testing methods. Your methods present misleading information about maximum power output on all amplifiers you have tested. this is applicable to all manufacturers, boxem, Buckeye, whoever.
So if Buckeye sends you a similar amp to boxems, are you going to make sure you test its max power at the same arbitrary and low thd level to be fair to both manufacturers? Or will it be another finger in the wind random level?
 

restorer-john

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No. You are making obviously facetious and spurious analogies. to be a substitute for the p501 it would need to perform similar in all areas which it doesnt. I have been specifically talking about what you term and label as the "max power output."
This is also why I suggested a second reading at 0.1%.


I have not mentioned March Audios p501.

Just to remind you of your previous post...
 

amirm

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Amir, I am not Alan.
Once again, you evade the question I asked you. I asked you if owner of a company asks as a imposter and when asked, continues to the kabuki theater, would you buy products from him or think twice about it?
 

JasonWells

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As @PeteL pointed out… but in a different wording… “at some point the power supply is what one hears.”




As a constructive criticism and alternate perspective.

^That^ reads as a bit more than “a hypothetical”.
Assuming it is in fact Alan, then it is a bit of a beat up session on his amp.
So his being banned (As Alan) kind of leaves no easy way to defend it.

I thought I read that Mr. March’s previous banning was for personal insults.
It is just a fact that some people use stronger language and a tone that is less accepting of technical errors.
And labelling it as impolite or rude is totally accurate… as no one likes to be called out, and humiliated.
But that does not change the truth technically.

Whether it is, or is not, Mr. March; maybe there could be a temporary ban lift when the thread is specifically about his products?
Much in the same way that the gentlemanly Erin had a temporary ban lift a while back.

Otherwise this thread can comes across as a beat up session, and one is vilified for coming back under nam de plumbe as being dishonest.
It is kind of a no win situation, and it certainly makes Alan and/or Jason not look questionable.
But it also can be perceived as a forum bias against him and his products.

It’s your forum, but the thread and tone, can be perceived in a negative way that splashes out beyond Jason to include ASR in general, and also Boxem and Buckeye And other amp makers that have opined. Everyone can get covered in the splash to a degree.

Please take this perspective only in the most positive way.
We kind of strayed from the technical aspects of the amp, to vilifying Jason.
It's not Alan. I don't know why he banned, before my time. i have only been readin the forum for a few months. I feel for him though, there appears to be something going here.
I don't understand why amir refuses to take on board any cryicism of his methods. you wont find anyone beyond this forum who thinks an amps max useable power is at 0.001% thd.
 

amirm

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I have not mentioned March Audios p501. this has been entirely about the testing methods.
You mean it is about angling to see if you can advantage yourself in this review. OP compared the power rating of your amp at full distortion in the sweep, to the minimum distortion of a competing product. This was wrong. It is my job to make sure fairness is applied, when I do my reviews and when others do the same and use my data. Past that, I have explained multiple times why what you are asking is already done in another test but you refuse to listen. All you want to do is let the misinformation in the original review stand in the hope of selling more gear. This is what I so dislike about you once you got in the business of selling audio products. You have no bounds, no ethics, no nothing when it comes to promotion of your audio products. And you will argue to death about it no matter how non-existent the foundation of your argument is.
 

JasonWells

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Once again, you evade the question I asked you. I asked you if owner of a company asks as a imposter and when asked, continues to the kabuki theater, would you buy products from him or think twice about it?
Yes, quite possibly.
 

Doodski

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It's not Alan. I don't know why he banned, before my time. i have only been readin the forum for a few months. I feel for him though, there appears to be something going here.
I don't understand why amir refuses to take on board any cryicism of his methods. you wont find anyone beyond this forum who thinks an amps max useable power is at 0.001% thd.
You make things too easy for testing with your methodology.
 

Vinyl Rules!

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I have followed this discussion and understood most of it, but I’m a noob when it comes to class D. I’ve used vintage solid state class A/B McIntosh amps for some time now.

I’m planning on purchasing a pair of Monitor Audio’s new Platinum 300 3G speakers. They present a four ohm load, efficiency is rated at 88dB, and Monitor Audio recommends amps offering 200 - 800 wpc. I’m considering some new, more powerful amps and on my shortlist are Van Alstine DVA M750’s rated at 1,000 watts into a four ohm load, and several different Buckeye class D amps rated at 500 watts into a four ohm load. If I chose the class D amps I would consider bi-amping the Monitor audio’s.

When I emailed Monitor Audio’s US distributor (Kevro International in Canada) for their thoughts, they recommended using a single 1,000 wpc amp on these speakers rather than bi-amping with two Buckeye 500 wpc amps.

So I’m soliciting thoughts on this, and if choose the 500 wpc class D amps, should I consider Buckeye Purifi or Buckeye Hypex?

TIA :rolleyes:
 
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JasonWells

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You mean it is about angling to see if you can advantage yourself in this review. OP compared the power rating of your amp at full distortion in the sweep, to the minimum distortion of a competing product. This was wrong. It is my job to make sure fairness is applied, when I do my reviews and when others do the same and use my data. Past that, I have explained multiple times why what you are asking is already done in another test but you refuse to listen. All you want to do is let the misinformation in the original review stand in the hope of selling more gear. This is what I so dislike about you once you got in the business of selling audio products. You have no bounds, no ethics, no nothing when it comes to promotion of your audio products. And you will argue to death about it no matter how non-existent the foundation of your argument is.
I want you to to have consistent testing methods precisely for the purpose of comparing products on a level playing field.
You are not doing that.
 

JasonWells

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As @PeteL pointed out… but in a different wording… “at some point the power supply is what one hears.”
As a constructive criticism and alternate perspective.
.
Otherwise this thread can comes across as a beat up session, and one is vilified for coming back under nam de plumbe as being dishonest.
It is kind of a no win situation, and it certainly makes Alan and/or Jason not look questionable.
But it also can be perceived as a forum bias against him and his products.

It’s your forum
, but the thread and tone, can be perceived in a negative way that splashes out beyond Jason to include ASR in general, and also Boxem and Buckeye And other amp makers that have opined. Everyone can get covered in the splash to a degree.

Please take this perspective only in the most positive way.
We kind of strayed from the technical aspects of the amp, to vilifying Jason.
It's abundantly clear that Amir has a personal problem with Alan. This sort of blatant bias and his inability to take on any criticism of his methods paints a pretty black picture of him and his forum.
I'm obviously not welcome here so it's time to go. plenty of other forums out there.
 

amirm

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I want you to to have consistent testing methods precisely for the purpose of comparing products on a level playing field.
You are not doing that.
Of course I am. I provide that precisely:

index.php


Every amp is tested for both static and dynamic power at 1% THD. So if it is precise power you want, it is in every review I do.

The sweep can never provide comparable power ratings because it lacks resolution in the max power region whether the knee is used or peak. Using the latter is nonsense as it doesn't provide a consistent distortion value for every amp which you claim you want. Nor does the sweep have enough resolution to show precise value.

I have explained all of this to you multiple times.
 

JasonWells

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Of course I am. I provide that precisely:

index.php


Every amp is tested for both static and dynamic power at 1% THD. So if it is precise power you want, it is in every review I do.

The sweep can never provide comparable power ratings because it lacks resolution in the max power region whether the knee is used or peak. Using the latter is nonsense as it doesn't provide a consistent distortion value for every amp which you claim you want. Nor does the sweep have enough resolution to show precise value.

I have explained all of this to you multiple times.
But again you contradict yourself. you say 1% is an unacceptably high distortion level, then use it in this test. Which is it?
Anyway, I'm not talking about this measurement. I'm talking about what you use to define your statement of "maximum power" read off the power sweep at an arbitrary thd level.

You already take measurements on a fairly steep part of the graph, do youvare just confirming its not accurate or consistent.
If it's not accurate why don't you either increase the number of measurement points in the sweep, or use the other method you cite as accurate to define the max power at a sensible level, say 0.1%?

This is just evasion after evasion.
 

amirm

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It's abundantly clear that Amir has a personal problem with Alan.
It has to be that, right? It can't be that your technical argument is wrong and you just want to promote your amp.

Despite knowing you are Alan, I let you post and post just like you always do, trying to sell us an unsellable argument to promote the amp at the expense of its competitor. Any reasonable person would look at those two sweeps and agree that the cursor should be put in the same place. But you are not reasonable, are you.

Remember, despite everything I know about you, I promoted the review of your product to home page.
 

amirm

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But again you contradict yourself. you say 1% is an unacceptably high distortion level, then use it in this test. Which is it?
1% is too high and hence the reason I continue to give the number at the knee of the curve. When I first started to perform that max and peak performance, I used 0.1%. Alas, vast majority of class D amps produced dismal power ratings due to their out of band noise. I had to go up to 10X that to get numbers to get them to produce reasonable numbers. In that sense, you and others producing class D amps are being advantaged this way. So if I were you, I wouldn't keep bringing this up.

For those not following, here is the Purifi FFT spectrum:

index.php


Notice how the noise rises above audible band to 100 kHz. That doesn't exist in class A/B amps but it serves to interfere in computation of THD+N.

So I suggest taking this gift and not keep harping on it.
 

JasonWells

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It has to be that, right? It can't be that your technical argument is wrong and you just want to promote your amp.

Despite knowing you are Alan, I let you post and post just like you always do, trying to sell us an unsellable argument to promote the amp at the expense of its competitor. Any reasonable person would look at those two sweeps and agree that the cursor should be put in the same place. But you are not reasonable, are you.

Remember, despite everything I know about you, I promoted the review of your product to home page.
I don't beleive it is wrong. I havent seen any justifacation for your methods. you are the only person i have seen who doesnt rate power at a fixed thd level. no one anywhere else rates max power at 0.001%, or the other similarly arbitrary low levels you do.
I won't comment on the rest. I'm not getting dragged into your personal issues. You are trying to deflect the technical argument
 
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JasonWells

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1% is too high and hence the reason I continue to give the number at the knee of the curve. When I first started to perform that max and peak performance, I used 0.1%. Alas, vast majority of class D amps produced dismal power ratings due to their out of band noise. I had to go up to 10X that to get numbers to get them to produce reasonable numbers. In that sense, you and others producing class D amps are being advantaged this way. So if I were you, I wouldn't keep bringing this up.

For those not following, here is the Purifi FFT spectrum:

index.php


Notice how the noise rises above audible band to 100 kHz. That doesn't exist in class A/B amps but it serves to interfere in computation of THD+N.

So I suggest taking this gift and not keep harping on it.
So why do you post the 1% continuius and burst measurements? You are contradicting yourself.

What on earth has a 1MHz graph got to do with anything????? do your measurements atcan appropriate bandwidth, 20Hz to 20kHz.
 
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amirm

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That's funny, I thought you used a 100kHz filter on the analyser. so how can the above 100kHz signals interfere with the thd +n computation?
Above? Who said anything about above 100 kHz. I said: "Notice how the noise rises above audible band to 100 kHz. "
 

JasonWells

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You mean this is not it?
index.php
Amir, you have stated repeatedly that 1% is too high. so why do you keep referencing this graph?
you state max power at arbitrary low levels.

For example:

Max power is 159 Watts at 0.001% thd+n 97.7dB

Note how the measurement point is on the steep part of the curve which you have stated its not possible to get accurate data from.

BoXem Arthur 4222E1 Monoblock Amplifier Power 8 ohm Measurement.png


So which is max power. the 1% thd bar graph, or the 0.001% power sweep.
 
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