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Marchaudio P501 Mono Block Power Amplifier Review

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thin bLue

thin bLue

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So you always measure your amps at DC?

//
The DC result was provided from Company.

But, I'm considering 34465A for cooler review! But the Nasdaq's hike ruined my poor account balance way worse before check-out. so pleas be patient.
In fact I am already patient(in many ways)! o_O
 

PeteL

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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)
That's already a nice effort and transparency from topping... They used to specify max power at 10% THD for their headphone amps without any mention of it. That's what I call fudging with number for marketing, but asking the whole industry to start to specify max power at inflexion point is not going to happen, especially since many amp don't even have an actual inflexion point, gotta be able to compare comparables.
 

MCH

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They don't!
Don't buy them!
They're USB-C DAC with 3.5 stereo output

Just Recycle Old useless cables!
USB(Type A or Typr C no metter if it can connectable to your PC) and 3.5 cable.

Marchaudio Amplifiers are working well with 5 V

View attachment 247412
View attachment 247411
View attachment 247413
Maybe something like this not to have to solder:
08639-01.jpg + mini-jack-st.jpg
 

restorer-john

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but asking the whole industry to start to specify max power at inflexion point is not going to happen, especially since many amp don't even have an actual inflexion point, gotta be able to compare comparables.

The actual standard (which is still in force) for advertised power ratings covers the range from 250mW to rated power across a specified bandwidth with a single distortion metric which is never exceeded at any point across the rated frequency range. It is not a cherry-picked best case THD (at the bottom of the curve) number to plaster all over your products. Or is it one that goes so far up the distortion curve that, just before the unit shuts down, you pick a power number. That, is deceptive. Purifi and Hypex (and some others for sure) just pick inflated headline best case figures because they think most high fidelity aficionados are ignorant. News flash! They aren't.

The rating in place, rules out picking 'inflexion' points, or 'knees' in the curve, because most of the time, the THD+N at 250mW is already way above the bottom of the curve where dubious manufacturers like to quote their numbers. With power amps, I'd draw a line from 250mW horizontally until it hit the upper power curve and you'd be on the money every time. The class Ds clip hard and fast- straight up. Plenty of other amps, are much slower and 'ease' into clipping. i.e. the shape of the curve is way less vertical.

This high powered March amplifier clearly performs very well, and has more than enough power for any domestic situation, but its 1kHz THD+N at 250mW means it would get an approximate rated 0.0025%THD+N from 250mW to 370/380W@4R. That would deteriorate significantly for a 20Hz-20kHz rating. Those numbers are not earth shatteringly excellent or game changing, but they are good.

It is not a 1kW high fidelity amplifier. It is well into complete non-linearity at or near that power output. That is the point Amir was making and it stands.
 
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antcollinet

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I'd draw a line from 250mW horizontally until it hit the upper power curve and you'd be on the money every time.
I like that method. Get both rated THD and Max rated power for that THD at the same time.
 

restorer-john

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I like that method. Get both rated THD and Max rated power for that THD at the same time.

Consider that a huge proportion of 'normal' musical listening happens at the lower end and it becomes even more valid.

250mW into a typical speaker is actually quite loud*. Even if you listen to much of the song/piece at a much higher level, the quiet parts, the detail and the reverb/echo will be around that figure.

Those guys back in the day who came up with the rating for advertising weren't stupid, that's for sure. :)

* a typical pocket 5 transistor radio with a 2 1/4" speaker back in the day played flat-out was about 200mW.
 
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thin bLue

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글쎄, 누구나 할 수 있지만 클리핑 포인트의 상단 부분을 선택하고 앰프의 전력으로 선언하는 것은 적절하지 않습니다.

index.php


아무도 그 수준의 왜곡에서 듣는 것을 기뻐하지 않을 것입니다. 왜곡이 거의 또는 완전히 수직이 되면 증폭기는 합리적인 작동 매개변수를 훨씬 뛰어 넘습니다.

또한 위의 AP 테스트는 THD+N을 캡처할 때까지 짧은 기간 동안만 앰프를 테스트한다는 점에 유의해야 합니다. 이것은 몇 분의 1초일 수 있습니다. 그래서 당신이 보는 것은 실제보다 더 순간적인 전력 수준입니다. 이것이 예를 들어 앰프가 전원 공급 장치 정격을 초과하는 전력을 생성할 수 있는 이유입니다. 저장소 캡은 이 테스트에 충분한 전력을 생성하지만 지속적으로 유지할 수는 없습니다.

따라서 귀하의 측정값이 내 측정값과 비슷하기를 원하는 한도 내에서(특히 내 측정값을 비교용으로 게시한 이후) 공정성과 적절한 분석을 위해서는 동일한 측정항목을 적용해야 합니다. 또는 전혀. 당신이 한 지점에 커서를 두는 것은 적절하지 않으며 이러한 방식으로 권력 수준을 과장하는 회사의 마케팅 메시지에 도움이 됩니다.


앰프의 최대 출력을 판단하기 위해 어떤 기준을 사용하는지 설명해 주시겠습니까?
그 기준으로도 포스팅할 수 있을 것 같아요!

Topping LA90 Measurements SNR Low Gain Power into 4 ohm Integrated Amplifier High Performance.png

THD+N 비율 0.00018%

Fosi Audio TB10D stereo amplifier cheap Power 4 ohm measurement.png

THD+N 비율 0.05077%

AIYIMA A07 TPA3255 Measurements power into 4 ohm.png

THD+N 비율 0.01691%

AUDIOPHONICS HPA-S400ET Measurements Low Gain Power into 4 ohm Balanced Purifi Stereo Amplifier.png

THD+N 비율 0.00024%

Loxjie A30 Amplifier Power into 4 ohm Measurements Analog Input.png

THD+N 비율 0.02086%

Apollon HYPEX NC2K BASED MONOBLOCK AMPLIFIER Power into 4 ohm Audio Measurements.png

THD+N 비율 0.03586%

BoXem Arthur 4222E1 Monoblock Amplifier Power into 2 ohm Measurement.png

THD+N 비율 0.00089%

BoXem Arthur 4222E1 Monoblock Amplifier Power into 4 ohm Measurement.png
THD+N 비율 0.00114%

-----
다른 회원의 편의를 위한 환산표
1%를 dB로 환산
20*로그(1/100)= -40dB

0.1%를 dB로 변환
20*로그(0.1/100)= -60dB

0.01%를 dB로 변환
20*로그(0.01/100)= -80dB

0.001%를 dB로 변환
20*로그(0.001/100)= -100dB)
----


BoXem Arthur 4222E1 Monoblock Amplifier Max and Peak Power into 4 ohm Measurement.png

일관성 있고 1 % 포인트가 합리적이라고 생각했습니다. 마케팅 메시지를 돕기 위한 것이 아닙니다. 나 자신 도 적절한 필터와 부하를 사용한
첫 번째 검토에서 1% 가치를 주장 했습니다. 양해 바랍니다.

당신은 오디오 사회의 진정한 후원자입니다.
그래서 내 목표는 당신처럼 사람들에게 정보를 제공하는 것입니다!
 
OP
thin bLue

thin bLue

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That doesn't make it proper. if someone can give me the link and confirm this is confidential information, I will delete it.
If so, treating of that, I will completely rely on you!
 

MCH

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In fact, I didn't solder, I just simply stripped the cable, twisted the coppers together, checked it worked, and re-insulated it!
We usually have a bunch of old cables that we never use. aren't you?


View attachment 247442
I would not recommended opening up a USB cable and joining conductors (without even specifying which) and then use that to connect a MacBook pro to an amplifier to someone that confused a dac with an adapter. Specially when a ready made hassle free cheap and available solution exists.
 
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thin bLue

thin bLue

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I would not recommended opening up a USB cable and joining conductors (without even specifying which) and then use that to connect a MacBook pro to an amplifier to someone that confused a dac with an adapter. Specially when a ready made hassle free cheap and available solution exists.
Oh..!
At that point, you are 100% right for that!
I didn't consider that detail.
 

Blumlein 88

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The actual standard (which is still in force) for advertised power ratings covers the range from 250mW to rated power across a specified bandwidth with a single distortion metric which is never exceeded at any point across the rated frequency range. It is not a cherry-picked best case THD (at the bottom of the curve) number to plaster all over your products. Or is it one that goes so far up the distortion curve that, just before the unit shuts down, you pick a power number. That, is deceptive. Purifi and Hypex (and some others for sure) just pick inflated headline best case figures because they think most high fidelity aficionados are ignorant. News flash! They aren't.

The rating in place, rules out picking 'inflexion' points, or 'knees' in the curve, because most of the time, the THD+N at 250mW is already way above the bottom of the curve where dubious manufacturers like to quote their numbers. With power amps, I'd draw a line from 250mW horizontally until it hit the upper power curve and you'd be on the money every time. The class Ds clip hard and fast- straight up. Plenty of other amps, are much slower and 'ease' into clipping. i.e. the shape of the curve is way less vertical.

This high powered March amplifier clearly performs very well, and has more than enough power for any domestic situation, but its 1kHz THD+N at 250mW means it would get an approximate rated 0.0025%THD+N from 250mW to 370/380W@4R. That would deteriorate significantly for a 20Hz-20kHz rating. Those numbers are not earth shatteringly excellent or game changing, but they are good.

It is not a 1kW high fidelity amplifier. It is well into complete non-linearity at or near that power output. That is the point Amir was making and it stands.
To be really picky, the old rules specified THD from 250 mw to rated power over 20-20,000 hz and not THD+N. It was often typical to measure a sweep with THD+N. I do remember Audio mag used to measure the power at 20hz, 200hz, 2khz and 20khz for this purpose. So the class D amp might do better if you leave out the N. My guess is it might have more THD near the 20 khz end like many switchers, but it might not.
 

JasonWells

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250mW into a typical speaker is actually quite loud*.
Would you agree a typical hifi speaker is probably about 85dB/2.83v/m? A 8 ohm speaker is 1 watt at this level. most speakers fall below this impedance and are less efficuent. 6 ohms a fair average?
So at 1 watt maybe 84dB/1m.
At 250mW this is 78dB at 1m. if you listen at 3m this falls to about 71dB. all rough numbers, but I don't think 71 dB is loud. doesn't Amir test at 5 watts because he considers it a typical listening level?
 
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Sokel

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The actual standard (which is still in force) for advertised power ratings covers the range from 250mW to rated power across a specified bandwidth with a single distortion metric which is never exceeded at any point across the rated frequency range. It is not a cherry-picked best case THD (at the bottom of the curve) number to plaster all over your products. Or is it one that goes so far up the distortion curve that, just before the unit shuts down, you pick a power number. That, is deceptive. Purifi and Hypex (and some others for sure) just pick inflated headline best case figures because they think most high fidelity aficionados are ignorant. News flash! They aren't.

The rating in place, rules out picking 'inflexion' points, or 'knees' in the curve, because most of the time, the THD+N at 250mW is already way above the bottom of the curve where dubious manufacturers like to quote their numbers. With power amps, I'd draw a line from 250mW horizontally until it hit the upper power curve and you'd be on the money every time. The class Ds clip hard and fast- straight up. Plenty of other amps, are much slower and 'ease' into clipping. i.e. the shape of the curve is way less vertical.

This high powered March amplifier clearly performs very well, and has more than enough power for any domestic situation, but its 1kHz THD+N at 250mW means it would get an approximate rated 0.0025%THD+N from 250mW to 370/380W@4R. That would deteriorate significantly for a 20Hz-20kHz rating. Those numbers are not earth shatteringly excellent or game changing, but they are good.

It is not a 1kW high fidelity amplifier. It is well into complete non-linearity at or near that power output. That is the point Amir was making and it stands.
So if I understand correctly this amp should be rated at 95-98 SINAD? That's what 0,002% is,isn't it?
 

Sokel

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Better re-hash Amirs entire SINAD table in that case
I wish there was a universal standard for 20Hz-20Khz SINAD.
(for example,the chart I posted in the previous page is an amp I'm using for 20Hz-300Hz tops (including the cross slope),it would be nice to know what I'm having there.I only have a hint now with the 100Hz measurement ((the blue line)) and that's according the company).
 

JasonWells

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I wish there was a universal standard for 20Hz-20Khz SINAD.
(for example,the chart I posted in the previous page is an amp I'm using for 20Hz-300Hz tops (including the cross slope),it would be nice to know what I'm having there.I only have a hint now with the 100Hz measurement ((the blue line)) and that's according the company).
Yeah, there is no technical standard for amps. I think Amirs chosen level of 5 Watts is sensible for a typical listening level. 250mW is not. 5 watts is about 84dB spl using the same assumptions as above. Otherwise you need to look at a full power v THD+N sweep.
 
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Sokel

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Otherwise you need to look at a full power v THD+N sweep.
I already asked for such measurements to be included but Amir said that with the proper bandwidth class D gives false results above 10Khz cause of the noise shaping (the inaudible one).
So it wouldn't be right.
 

JasonWells

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I already asked for such measurements to be included but Amir said that with the proper bandwidth class D gives false results above 10Khz cause of the noise shaping (the inaudible one).
So it wouldn't be right.
FWIW my view is the measurement bandwidth should be 20kHz. that's what you can hear. remember WRT THD this means that the fundamental doesn't need to go above 6.7kHz for 3rd harmonic and 10kHz for the second.
always worth looking above 20kHz to see if any weird/bad stuff is going on though, but how bad would it need to be to become audible? DSD advocates still love it regardless of the massive ultrasonic shaped noise it has.
 
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restorer-john

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To be really picky, the old rules specified THD from 250 mw to rated power over 20-20,000 hz and not THD+N. It was often typical to measure a sweep with THD+N. I do remember Audio mag used to measure the power at 20hz, 200hz, 2khz and 20khz for this purpose. So the class D amp might do better if you leave out the N. My guess is it might have more THD near the 20 khz end like many switchers, but it might not.

To be equally picky, I think you've forgotten that the FTC rules were instigated in 1974 and the only valid way of measuring THD included noise. There was no computerised FFT back then. Spectrum analysers were not even capable of high resolution measurements.

The standard measurement notched out the fundamental and measured the remainder. All THD meters worked that way.

It was the Audio Precision System One in about 1988/9 which re-defined the THD and N as separate and measurable metrics. Prior to that, we could measure residual and residual + distortion.
 
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