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Marchaudio P501 Mono Block Power Amplifier Review

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JasonWells

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Regardless of the arbitrary graphing, anyone who believes for even an instant that the same Hypex/Purifi modules with identical or similar power supply could deliver wildly different results should go back to their homework. Yes, there are clear indications that some integrators 1) do a better job in routing cables, which can get them a few more dBs of SNR 2) have better QC but this isn't what it is about.

As far as the semi-arbitrary max power levels Amir provides are concerned, while they don't necessarily allow for strict numerical comparison, we also all should know that this is where Amir estimates the amp starts to break down. Given that different amp architectures break down in different ways, I don't see how you can avoid some fuzziness.
Would you feel an amp is "breaking down" at 0.001% thd? it's quite simple to take the measurement at a consistent thd level.

I'm off to watch some soccer.
 
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PeteL

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Regardless of the arbitrary graphing, anyone who believes for even an instant that the same Hypex/Purifi modules with identical or similar power supply could deliver wildly different results should go back to their homework. Yes, there are clear indications that some integrators 1) do a better job in routing cables, which can get them a few more dBs of SNR 2) have better QC but this isn't what it is about.

As far as the semi-arbitrary max power levels Amir provides are concerned, while they don't necessarily allow for strict numerical comparison, we also all should know that this is where Amir estimates the amp starts to break down. Given that different amp architectures break down in different ways, I don't see how you can avoid some fuzziness.
This one has a different power supply, that's the point.
 

pkane

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I'm not. I just don't see any valid justification for the random extremely low thd levels amir chooses. See my points above about the relevance of measurements.

Amir doesn’t chose THD values at all when reporting the knee transition point — you seem to want to use THD level as the only metric for some reason. He picks the point where the amp transitions from its normal operating mode into an increasingly nonlinear region. THD value at that point is irrelevant to this measure. I’d prefer to know where this point is and avoid it, if possible, even if you claim the distortion is still inaudible there.
 

Buckeye Amps

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OK, you and boxem make similar amps. what if Amir measures yours at 0.001% and boxems at 0.01%. yours will look inferior WRT power. that's what he is doing. I would have thought you would want a level playing field.
In this hypothetical I would obviously rub it in @boXem | audio that my amp is cleaner sounding :cool:
(In case it isn't obvious, this is sarcasm people)

But really, if Amir were to show that at the knee, right as distortion is beginning to rise amp A is 200w @ 0.001% and amp B is 250w @ 0.01%...those are valid and usable results for me I can show my customers irt power vs. distortion.

Then I could also tell my customers "but if max power is more important, here is how my amps max W measured at x%"

What seems to be overlooked is Amir has clearly said thin blue can continue measuring and posting reviews the way he did here BUT if he wants to compare his findings against another amps findings from a different review either use the same protocol OR make an obvious disclaimer for readers who may not be doing a technical dive into the data.
 

Blumlein 88

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Totally off topic but what was that circuit NAD built into their old integrateds, "soft clipping"? My 3140 has it.
I don't know, but McIntosh had the old PowerGuard circuit to prevent clipping and it was very effective. Of course if you just kept pushing the level it became something of a compressor, but still didn't allow tons of distortion.
 

DualTriode

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Of course within operating range, I agree there is almost no audible difference.

What I'm referring to is the scenario of someone with 2ohm speakers (or even a subwoofer) where the 400a is being pushed to its limit or even past, the 7040sa would be am advantage and that's when you may hear a difference (since the 400a in this scenario may be clipping but the 7040sa isn't).

Again, a niche scenario for sure.

Unless golden ears are calibrated we do not care what they hear.

We are talking objective instrumentation, as in SINAD
 

AdamG

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OK fellas let’s dial back the sarcasm please. Disagree nicely or move along. We have a very highly technical group here. I feel pretty confident that they can see what the tests and graphs indicate. Labels affixed by the Author are not the final arbiter. The data speaks for itself. Can we just move along. If you fellas want to continue this “Power Knee” conversation, create a new thread and knock yourselfs out.

Oh,,,,Please and thank you! :cool:
 

Ajax

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Hi All,

Change of topic, however, I don't think off topic.

After researching the March, Audiophonics and BoXem hypex range of amps I decided on the Buckeye NC 252MP @ 150W into 8 Ohms for US$579 plus shipping to Australia. https://www.buckeyeamp.com/shop/p/hypex-nc252mp-amplifier-2-channel

This amp was "measured" by Amir (ASR) in a 6 channel set up and he described the THD + N ratio as excellent and the signal to noise ratio as superb.


Archimago also built the NC252 as a DIY project and then measured:


In his review(s) he stated:

"If 150W into 8Ω, 250W into 4Ω, and even 180W into 2Ω is all the stereo power you need, it's going to be very hard to justify the "need" for something of even higher fidelity.

What I'm excited by is the idea of ongoing refinement, even better power efficiency, smaller physical footprint, and of course even lower prices in the days ahead as technology marches forward and provides value to those seeking high fidelity audio. Progress does not look or sound like 100-pound solid state behemoths or anachronistic tube-jobs costing 4+ figures, IMO. Rather, this amplifier is a nice example of high-fidelity in the real world of the 21st Century - potentially unassuming devices that can provide beautifully clean, "clinical", and some might even call "sterile", empty, sonic canvases upon which the "colors", noise, "grunge", and harmonics of your music arises from with ease.

At some point, as much as some audiophiles want to believe that they're always hearing better and better sound (ironic because as we get older past our prime, our ears get worse!), we need to contend with the idea that technology has already matured to the point where there really is no further audible fidelity to achieve. Beyond the point of transparency, we're simply left with subjective idiosyncratic preferences.

This amplifier has more than enough resolution for hi-res digital playback; the question is whether the rest of your audio chain can maintain the fidelity. For sure, one can spend more money and achieve even lower noise level and lower distortions (yeah, I know, the Benchmark AHB2, Hypex NC400, NC500, and Purifi amps are all awesome - anyone got level-controlled blind test results to show audible differences?!)."

If you really do need more power (electrostatics) you can choose the NC502 with double the power (300W+ into 8 Ohms) for only another US$180.

So why are we continuing this mindless, and to me meaning less, search for higher and higher fidelity, when for less than US$1,000 you can get a transparent and bit perfect front end ...... simply add your own computer or streamer (computer chromecast audio or raspberry pi) with a Topping or SMSL DAC.

So why are we are going down this rabbit hole. Why are we sweating the small stuff when there are bigger fish to fry.

It would be great if we could put more focus and more of our efforts where we will get the biggest rewards - speakers, DSP and room set up. Linkwitz had the right idea.
 
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Doodski

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for less than US$1,000 you can get a transparent and bit perfect front end ...... simply add your own computer or streamer (computer chromecast audio or raspberry pi) with a Topping or SMSL DAC.
Don't forget JDS Labs and Schiit for a DAC.
 

amirm

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So why are we are going down this rabbit hole. Why are we sweating the small stuff when there are bigger fish to fry.
Because these well engineered products are a fraction of overall market and for the most part, ignored by audiophiles. Had we not put the spotlight on them, they may have not even materialized or stayed in market. We are the wind behind these companies to get the recognition they deserve vs sea of marketing and brand recognition by others that lead the market.
 

amirm

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How do you draw that conclusion? I have been very clear this isn't about any specific distortion level. it's about your reasoning for the numbers you are producing and expecting thin blue to follow suit.
Where does thin blue take the measurement on the knee?
I didn't ask you any of this. I asked if just about any distortion will do including 1%, then why would anyone shop for this amplifier when they can get a pro amp for a fraction of its price ($360 in this case):

index.php


If I go by the logic of putting the cursor at the highest point, it would be 900 watts/channel which is almost the same as the March amplifier being tested. By your logic, this Rockville amp is a perfect substitute for the P501, yes?
 

amirm

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@restorer-john I assume you are referring to Alan March of March Audio. that's not me.
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 ;).
 

Ajax

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Because these well engineered products are a fraction of overall market and for the most part, ignored by audiophiles. Had we not put the spotlight on them, they may have not even materialized or stayed in market. We are the wind behind these companies to get the recognition they deserve vs sea of marketing and brand recognition by others that lead the market.
Thanks for your reply Amir, make no mistake I am very grateful for your work. You have done an amazing job introducing us to well engineered products that are inexpensive to boot.

I have followed your recommendations and now own several systems consisting of old Sonos (not interested in high res) and chromecast audio streamers (with optical out) into Topping & SMSL DACs and Hypex amplifiers. I therefore have several front ends that are user friendly, with low distortion, low noise, high signal to noise ratio, bit perfect and with enough power to drive any speaker. My point is that due to your work an affordable front end is now readily available and within everybody's reach.

As an engineer (Civil) I understand that excellence in engineering is a worthy goal in itself. However, a chain (system) is only as strong as it's weakest link and if I'm thinking strategically about the future for ASR then IMO we need to turn our focus more to the back end. You are already measuring speakers but I personally would like more info (case studies) on DSP and room treatment.

How do you and the rest of the ASR community feel we can continue to move forward and assist music lovers to get the best possible sound (for the least amount of $). What's ASR's next step in helping consumers get the best bang for their buck.

I say all this with the knowledge that you can only test what you receive.

Thanks again for everything.
 
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Holmz

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Regardless of the arbitrary graphing, anyone who believes for even an instant that the same Hypex/Purifi modules with identical or similar power supply could deliver wildly different results should go back to their homework. Yes, there are clear indications that some integrators 1) do a better job in routing cables, which can get them a few more dBs of SNR 2) have better QC but this isn't what it is about.

As far as the semi-arbitrary max power levels Amir provides are concerned, while they don't necessarily allow for strict numerical comparison, we also all should know that this is where Amir estimates the amp starts to break down. Given that different amp architectures break down in different ways, I don't see how you can avoid some fuzziness.

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


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 ;).

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.
 

Fahzz

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Because these well engineered products are a fraction of overall market and for the most part, ignored by audiophiles. Had we not put the spotlight on them, they may have not even materialized or stayed in market. We are the wind behind these companies to get the recognition they deserve vs sea of marketing and brand recognition by others that lead the market.
Pretty much the mission statement for ASR. Kudos.
 

PierreV

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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.

Not sure why. Didn't he ask to be banned at some point, as a way of spectacularly marking his discontent?

Up until the repackage khadas tone board 'crisis' (Alan was selling a Khadas Tone Board in a nicer box with a steep, but understandable markup - some people complained it was not disclosed and Alan handled the situation very poorly from a PR point of view imho), Alan was a very nice, very competent and very helpful member of this board. I can certainly credit him for a few of the things I learned here. I certainly do miss that version of Alan.

But it went very, very much downhill from there...

I don't miss Alan 2.0
 

JasonWells

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I didn't ask you any of this. I asked if just about any distortion will do including 1%, then why would anyone shop for this amplifier when they can get a pro amp for a fraction of its price ($360 in this case):

index.php


If I go by the logic of putting the cursor at the highest point, it would be 900 watts/channel which is almost the same as the March amplifier being tested. By your logic, this Rockville amp is a perfect substitute for the P501, yes?
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%.
 
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