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March Audio P502 Stereo Amplifier Measurements

yodog

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Possibly a good place to mention that we have just started shipping all amps with ETI solid copper gold plated binding posts. These offer better access for large cables and spades than the previous ones shown in the review. The materials used will also provide significantly improved audiophile satisfaction ;)

https://eti-research.com.au/binding-post-bp-20c/
View attachment 45939View attachment 45940
Is there any way to substitute eti research silver posts for a premium? Or wbt silver posts? How much is this amplifier?
 

March Audio

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Is there any way to substitute eti research silver posts for a premium? Or wbt silver posts? How much is this amplifier?
Hi @yodog

Yes we can fit the ETI Kryo posts.

KryoBP-WR2.png


Please email to discuss

[email protected]

Best regards

Alan
 

thebible

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when using the p502 after a short period of time the amp gets really warm. is this expected? i dont feel like i am putting much load to the amp itself. beyond that its working great
 
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Listen first

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Alan, just wanted to say that you have the patience of a saint to deal with some ridiculous mud slinging on this thread. Thank you for the clarity and integrity. I know that manufacturers can get a real hard time on here but I thought that was only the ones who don’t engage!
Your engagement is very good, credible and sets the standard for others.
I will certainly consider your products for future listening.

Hi @yodog

Yes we can fit the ETI Kryo posts.

View attachment 71848

Please email to discuss

[email protected]

Best regards

Alan
 

thepiecesfit

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Perhaps best asked to @March Audio but with a cable such as the XLR to RCA unbalanced, are we expecting 6dB loss of gain? Has this been measured? What kind theoretical max power can one expect pairing this unit with an AVR that may start clipping around 2v with an unbalanced connection.
 
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McFly

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I think Alan mentioned that 2V from an RCA unbalanced source will still drive the amps to full power with the cable correctly terminated
 

pma

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Perhaps best asked to @March Audio but with a cable such as the XLR to RCA unbalanced, are we expecting 6dB loss of gain? Has this been measured? What kind theoretical max power can one expect pairing this unit with an AVR that may start clipping around 2v with an unbalanced connection.

No, the amplifier gain is always the same. However, the unbalanced output voltage of the preceding component (DAC, preamp) would be almost always half of the balanced output. Usual balanced output voltage of the DAC is 4Vrms and unbalanced output 2Vrms. Maximum output voltage of the amplifier would be

Vout = G(amp) x Vs

Vs ... source output voltage (DAC, preamp)
G(amp) ... amplifier gain
Vout ... amplifier output voltage

Vout max. value would be limited by amplifier clipping voltage
 

blodsbror

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Just a general question.
The price to power ration of the 502 looks fantastic on paper. (as in general for Class D) Given that, is there really any reason to go down the Class A/B route, aside from simply getting a different sonic presentation in addition to using more power ? As an example (I'm in Norway) The Hegel H30 power amplifier gives you 350 watts into 8 ohms, and is 10,000 USD.

Why would anyone spend that kind of money, when something like the 502 gives you the same power for 1/10th of the cost ? Can 350 watts of class A/B power with a huge power supply, drive speakers that the 502 cannot ?. Great if someone can enlighten me :)
 
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arisholm

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Just a general question.
The price to power ration of the 502 looks fantastic on paper. (as in general for Class D) Given that, is there really any reason to go down the Class A/B route, aside from simply getting a different sonic presentation in addition to using more power ? The Hegel H30 power amplifier gives you 350 watts into 8 ohms, and is 10,000 USD.

Why would anyone spend that kind of money, when something like the 502 gives you the same power for 1/10th of the cost ? Can 350 watts of class A/B power with a huge power supply, drive speakers that the 502 cannot ?. Great if someone can enlighten me :)
Not sure, but apparently there should be no reason to get the Hegel as long as you trust that the measurements into a 8 ohm resistor tell the whole story?
 

blodsbror

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Not sure, but apparently there should be no reason to get the Hegel as long as you trust that the measurements into a 8 ohm resistor tell the whole story?

I have no idea. ;) iI you look at the price to performance ratio, I'm just trying to understand why someone would spend 10 times more - if it's just potentially a change in sound, and not ability to drive the speakers. I just used the Hegel as a class AB example :). Am just looking for more of a general explanation from people with much more experience than me in regards to Class D (Ncore, Purifi) vs very expensive Class AB. Will the Class AB, potentially just sound "subjectively" better ?
 

Matias

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Just a general question.
The price to power ration of the 502 looks fantastic on paper. (as in general for Class D) Given that, is there really any reason to go down the Class A/B route, aside from simply getting a different sonic presentation in addition to using more power ? As an example (I'm in Norway) The Hegel H30 power amplifier gives you 350 watts into 8 ohms, and is 10,000 USD.

Why would anyone spend that kind of money, when something like the 502 gives you the same power for 1/10th of the cost ? Can 350 watts of class A/B power with a huge power supply, drive speakers that the 502 cannot ?. Great if someone can enlighten me :)
In my experience the NC502MP is very, very good. And in my opinion is a killer value, I would consider high end class A or AB if all my system has been maximized, like dedicated and treated room, great speakers and source, etc.
 

blodsbror

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In my experience the NC502MP is very, very good. And in my opinion is a killer value, I would consider high end class A or AB if all my system has been maximized, like dedicated and treated room, great speakers and source, etc.

Thanks. But what do you feel (or know) a higher end and expensive class AB would give you over the 502 ? In my example, the 8 ohm wattage, is exactly the same.
 

SIY

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Thanks. But what do you feel (or know) a higher end and expensive class AB would give you over the 502 ? In my example, the 8 ohm wattage, is exactly the same.

Zero. Sonically, they'll be indistinguishable (assuming an engineered linear amp).
 

blodsbror

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Zero. Sonically, they'll be indistinguishable (assuming an engineered linear amp).

Right. So a well designed, and transparent (as possible) class AB design is basically pointless. And especially pointless when its multiple factors more expensive than the 502 (or Purifi) March Audio amps. If there is some objective and measurable benefit of an expensive AB over the 502, then I would love to see it :)
 

AudioTodd

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I think the primary claim would be that a beefy class AB amp that expensive would (should) be able to deliver enough current to double its power with every halving of the load impedance down to a ridiculous level and do so with rock solid stability such that the amp was as close to completely indifferent to load as possible while maintaining its top performance.

How well this is achieved in practice varies.

Is that additional margin, if it does exist, over an excellent class D worth the cost, especially if it is likely to only exist as audiophile peace of mind rather than an audible difference? I guess that depends on the value you place on money!!

I have everything from low watt single ended triode amps to solid state class A to the recent acquisition of Apollon Audio purifi-based monoblocks and generally find they all sound good when operated appropriately (with the right speakers and at the right levels). My high current amps are not speaker-dependent and I have not noticed anything out of place with the purifi amps, but I didn't expect to, and have not sensed they have any problem driving Magnepan .7s, which is the only pair of speakers I have used them with. That doesn't give me a LOT to analyze, but the .7s have some oddities to their loan characteristics and I have not found any effect on the sound having them driven by the Apollon purifi implementation.

Lots of words to basically say "I don't know why someone would spend $9,000 more for the Hegel."
 

blodsbror

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I think the primary claim would be that a beefy class AB amp that expensive would (should) be able to deliver enough current to double its power with every halving of the load impedance down to a ridiculous level and do so with rock solid stability such that the amp was as close to completely indifferent to load as possible while maintaining its top performance.

How well this is achieved in practice varies.

Is that additional margin, if it does exist, over an excellent class D worth the cost, especially if it is likely to only exist as audiophile peace of mind rather than an audible difference? I guess that depends on the value you place on money!!

I have everything from low watt single ended triode amps to solid state class A to the recent acquisition of Apollon Audio purifi-based monoblocks and generally find they all sound good when operated appropriately (with the right speakers and at the right levels). My high current amps are not speaker-dependent and I have not noticed anything out of place with the purifi amps, but I didn't expect to, and have not sensed they have any problem driving Magnepan .7s, which is the only pair of speakers I have used them with. That doesn't give me a LOT to analyze, but the .7s have some oddities to their loan characteristics and I have not found any effect on the sound having them driven by the Apollon purifi implementation.

Lots of words to basically say "I don't know why someone would spend $9,000 more for the Hegel."


Much appreciated. Some great insight. And a good story :). That said, with a lot of the (especially Purifi) based Class D implementations - they mention that they are very stable down to 2 ohms (if I read correctly). So again, that negates that benefit of this massive power supply in the Hegel example - if the end result is basically the same. At least in my relatively new eyes. It's just mind blowing to get my head around, if this is really the case. Unless, it simply gives a "different" sound, that one prefers with the Hegel. Which is totally fine. But yes, 9000 USD more, for me, is just a big NO ;). Appreciate the input here.
 

Billy Budapest

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Right. So a well designed, and transparent (as possible) class AB design is basically pointless. And especially pointless when its multiple factors more expensive than the 502 (or Purifi) March Audio amps. If there is some objective and measurable benefit of an expensive AB over the 502, then I would love to see it :)
Class AB designs with switching power supplies are an interesting area of technology—but there aren’t many of those to choose from. Still, the topology is extremely inefficient compared to class D. I don’t see any compelling reason to purchase a class AB (with a linear power supply) amp over a class D. Further, most class AB amps are going to be audibly transparent and can’t be used as a “tone control” the way class A and tube amps can be. So, with a choice between class D and class AB, class D will win for me every time.
 

blodsbror

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Class AB designs with switching power supplies are an interesting area of technology. Still, the topology is extremely inefficient compared to class D. I don’t see any compelling reason to purchase a class AB amp over a class D. Further, most class AB amps are going to be audibly transparent and can’t be used as a “tone control” the way class A and tube amps can be. So, with a choice between class D and class AB, class D will win for me every time.

That's where something like the 502 or 452 with a Tube pre (Schiit Freya + for example) could be a formidable combination. Or even a simple Schiit Loki for tone controls.
 
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