The state of the art class D AUDIOPHONICS HPA-S600NC and AUDIOPHONICS HPA-S400ET sound different, though there is a caveat here.

[Jimbob54]

I see the logic of not having a worse measurement at the beginning but not the logic of having a worse measurement at the end.

That's not a goal, that's just the way it is. The speakers/ headphones are orders of magnitude noisier/ distortion heavy than the electronics that drive them. And as flanker says, you wouldnt choose a DAC today that has more noise or distortion than the amp it sits behind.

 

[ommadusk]

But if an 'excellent' SINAD for a DAC is 114-115dB higher than an amp doesn't that potentially open up a scenario whereby the sound quality is being reduced within the audible range? I'm just a layperson.

P.S. I suppose that's why there's a lot of measurements to look at.

 

[SIY]

But if an 'excellent' SINAD for a DAC is 114-115dB higher than an amp doesn't that potentially open up a scenario whereby the sound quality is being reduced within the audible range?

Potentially, but generally unlikely. An amp that's reasonably quiet but has SINAD limited by distortion to, say, 80dB, is still likely to be audibly transparent.

I'm not a fan of SINAD as a ratings number rather than an engineering number just because it lumps together too many disparate things. I'd look at noise and distortion as separate issues.

 

[ommadusk]

Potentially, but generally unlikely. An amp that's reasonably quiet but has SINAD limited by distortion to, say, 80dB, is still likely to be audibly transparent.

I'm not a fan of SINAD as a ratings number rather than an engineering number just because it lumps together too many disparate things. I'd look at noise and distortion as separate issues.

I suppose then both these amps fall would into the certainly impossible category .

 

[MaxwellsEq]

I'm not a fan of SINAD as a ratings number rather than an engineering number just because it lumps together too many disparate things. I'd look at noise and distortion as separate issues

Agreed I like to see the output noise voltage as a single number. I also begin to think it would be useful both in the audio band and also wider.

 

[ommadusk]

Lots of people have said that. Why would the number be useful outside the audible band?

 

[antcollinet]

I see the logic of not having a worse measurement at the beginning but not the logic of having a worse measurement at the end.

It is much harder to make amps with very low distortion, and it is even harder still with transducers.

So the best of the best amps (exellent category) will never achieve the same figures as the best of the best DACs. So necessarily the targets have to be different.

 

[AdamG]

Yes.

No.

I have both a Purifi and an NCx500. Within power limits, they sound identical.

Hi SIY,

Thanks for the correction. I got Speaker testing methods mixed into the Amp testing with a Voltmeter/Multimeter. I hereby issue myself a few .

Original post is now edited to prevent confusion.

 

[MaxwellsEq]

Lots of people have said that. Why would the number be useful outside the audible band?

Noise above the audible range may affect downstream badly designed items. I have a conjecture that some people's perceptions of sonic differences are caused by unstable audiophile devices being incorrectly sensitive to HF and RF noise on their inputs. But it's just a theory.

 

[ommadusk]

I love this amp. I've been playing music for about 4 days non-stop. No 'brightness' on my Polk R200 speakers that I'd experienced with the PA5 and Audiophonics HPA S600NC. The PA5 was underpowered for them. I'm not worrying about my hearing loss anymore. I'd bet my life anyone with reasonable hearing including your good selves could hear the difference. Why? I don't know. I was assuming it was the components but maybe I was wrong. Is this the correct sound? Probably but I can't be sure. It's very enjoyable. I hope I've helped someone by saying I love this amp. In case anyone's wondering, I'm objective. I don't think anyone's subjective if you inform them of the facts.

 

[Deleted member 48726]

I love this amp. I've been playing music for about 4 days non-stop. No 'brightness' on my Polk R200 speakers that I'd experienced with the PA5 and Audiophonics HPA S600NC. The PA5 was underpowered for them. I'm not worrying about my hearing loss anymore. I'd bet my life anyone with reasonable hearing including your good selves could hear the difference. Why? I don't know. I was assuming it was the components but maybe I was wrong. Is this the correct sound? Probably but I can't be sure. It's very enjoyable. I hope I've helped someone by saying I love this amp. In case anyone's wondering, I'm objective. I don't think anyone's subjective if you inform them of the facts.

If you like the sound then all is well. That is the most important thing. Happy listening.

 

[ommadusk]

If you like the sound then all is well. That is the most important thing. Happy listening.

No, I said I love it or is that wrong and I think it's the only thing that matters.

 

[antcollinet]

Noise above the audible range may affect downstream badly designed items. I have a conjecture that some people's perceptions of sonic differences are caused by unstable audiophile devices being incorrectly sensitive to HF and RF noise on their inputs. But it's just a theory.

But for an amp, the only downstream component is going to be a speaker (or headphone). I don't think they are going to be adversely affected by ultrasonic noise - unless it were to get to levels to create significant dissipation in the tweeter - which I really can't imagine happening.

 

[Matias]

@ommadusk isn't the AUDIOPHONICS HPA-S600NC based on NCore NC500 OEM, and not NCoreX NCx500 OEM? I think you got and are comparing the former generation and not the current.

Their model with NCx500 is AUDIOPHONICS HPA-S600NCX.

 

[ommadusk]

@ommadusk isn't the AUDIOPHONICS HPA-S600NC based on NCore NC500 OEM, and not NCoreX NCx500 OEM? I think you got and are comparing the former generation and not the current.

You're right! I got the thread title wrong. I'm not able to change it now. I bought the HPA-S600NCX. Thank you.

​

 

[ommadusk]

@Matias what made you think I bought and was comparing the wrong amp?

 

[Matias]

Ok, just checking. The title was wrong indeed.

Also, you could try opamps rolling, taking out the Texas Instrument LM4562 and replacing with OPA1656 for example.

 

[ommadusk]

Ok, just checking. The title was wrong indeed.

Also, you could try opamps rolling, taking out the Texas Instrument LM4562 and replacing with OPA1656 for example.

No. You said you thought I bought and was comparing the wrong amp. I've been talking about the NCX500 in the thread so what made you think I bought the wrong amp or haven't you been reading the thread? I don't want to jump to any wrong conclusion. I've returned the other amp now.

You avoided the question.

 

[ommadusk]

I'll make a conclusion and then people can judge me for that. You wanted to think there was another difference between the two amps that the one I was talking about. Why? Is it because you're afraid of being seen as independent? I'm putting that as positively as I can.

P.S. You suggested changing the op amps as if that's going to make it better. That's irresponsible advice.

 

[antcollinet]

I'll make a conclusion and then people can judge me for that. You wanted to think there was another difference between the two amps that the one I was talking about. Why? Is it because you're afraid of being seen as independent? I'm putting that as positively as I can.

Perhaps it is just because the heading was wrong?