Review and Measurements of Purifi 1ET400A Amplifier

[March Audio]

Damn, that was a hell of an Ego trip...

With tantrum post to boot. . The classic Audiophile "test tones aren't music" misunderstanding with a dash of denying everything he actually said. There was a lot of "we don't know" and "what if". Oh, and obviously has not looked enough around the site to notice the 32 tone tests.


Oh well, back on topic

 

[mocenigo]

And there again you betray your lack of understanding of the subject. As such there is no point in trying to go through your last posts.

Just one thing though.

"To the risk of being banned, where did I f*cking say that R2R is better?"

That would be here;

"they will represent transients more faithfully."

Which is just ONE parameter out of many. And yet this is in fact true, and even acknowledged by many designers of DS DACs (usually as the “only” and only potential problem with their designs). I also have no problems in admitting that in general R2R DACs have higher noise and distortion levels than DS DACs. So it seems that I might have touched a nerve and somebody here is not understanding what I am saying.

 

[mocenigo]

With tantrum post to boot. . The classic Audiophile "test tones aren't music" misunderstanding with a dash of denying everything he actually said. There was a lot of "we don't know" and "what if". Oh, and obviously has not looked enough around the site to notice the 32 tone tests.

Oh well, back on topic

you are getting ridicolous. I did mention multi tone tests. And, yes, it has nothing to do with music. Also, I am not an audiophile.

 

[March Audio]

Which is just ONE parameter out of many. And yet this is in fact true, and even acknowledged by many designers of DS DACs (usually as the “only” and only potential problem with their designs). I also have no problems in admitting that in general R2R DACs have higher noise and distortion levels than DS DACs. So it seems that I might have touched a nerve and somebody here is not understanding what I am saying.

Cite your evidence please.

 

[March Audio]

you are getting ridicolous. I did mention multi tone tests. And, yes, it has nothing to do with music. Also, I am not an audiophile.

Yes it is. Music is not necessary to test for distortions. It's a typical Audiophile myth.

What do you think 32 tones all going up and down in amplitude at different rates is doing?

More to the point, what extra issues does playing music produce and demonstrate?

 

[mocenigo]

Cite your evidence please.

A couple of hints: A famous ESS white paper, and also a post by a DS DAC designer here on ASR.

 

[JohnYang1997]

A couple of hints: A famous ESS white paper, and also a post by a DS DAC designer here on ASR.

Those aren't evidence nor proof.

 

[mocenigo]

Yes it is. Music is not necessary to test for distortions. It's a typical Audiophile myth.

What do you think 32 tones all going up and down in amplitude at different rates is doing?

More to the point, what extra issues does playing music produce?

Ok, I may have misunderstood. I thought about the static tones test. This one would be/is fine.

 

[mocenigo]

Those aren't evidence nor proof.

Please read. i said that even DS DAC designers are aware. If they talk about this potential weakness, why should they if it does not exist? Mind you, the alternative explanation is worse.

 

[March Audio]

Ok, I may have misunderstood. I thought about the static tones test. This one would be/is fine.

No its the "static amplitude test" you are thinking of. What you seem to forget is that a sine wave is not actually "static amplitude". A sine wave is a transient signal in the way you are thinking, just a repetitive one.

 

[March Audio]

A couple of hints: A famous ESS white paper, and also a post by a DS DAC designer here on ASR.

No, cite the issue, cause and effect, and show the real world impact compared to an R2R dac.

 

[JohnYang1997]

Please read. i said that even DS DAC designers are aware. If they talk about this potential weakness, why should they if it does not exist? Mind you, the alternative explanation is worse.

You can say you are professor, scientist all you want. You lack critical thinking and/or lack required related knowledge. Think about signal processing. Think human auditory system as a filter. Think about how actually time domain and frequency domain react. 32 tones have to all beat to each other in time domain. The tones themselves are static in frequency domain. You can certainly add a sweeping signal at a higher frequency as well but that wouldn't change things. Think about control theory how DS work, how the stability realized, the frequency of 20khz comparing to the operating frequency of dacs. This just can go on and on and on. You ask those questions and think that way and saying who you are makes me feel really really weird.

 

[mocenigo]

No its the "static amplitude test" you are thinking of. What you seem to forget is that a sine wave is not actually "static amplitude". A sine wave is a transient signal.

Ah, for going up and down you meant the sine waves. So the spectrum would be a series of lines. I do know what a sine wave is, and mocking me pretending to talk to a baby is not going to help the image you have made of yourself. If I think that I even wrote to you to express my solidarity wrt troll attacks... And then you come up with "A sine wave is a transient signal". When it starts and ends, yeah, otherwise it is static.

I constantly speak of how the signal looks in the spectrum (the Fourier space) and then you come up with this. Pathetic.

 

[JohnYang1997]

Ah, for going up and down you meant the sine waves. So the spectrum would be a series of lines. I do know what a sine wave is, and mocking me pretending to talk to a baby is not going to help the image you have made of yourself. If I think that I even wrote to you to express my solidarity wrt troll attacks... And then you come up with "A sine wave is a transient signal". When it starts and ends, yeah, otherwise it is static.

I constantly speak of how the signal looks in the spectrum (the Fourier space) and then you come up with this. Pathetic.

No. You have no idea how two or more sines react in time domain.

 

[March Audio]

Ah, for going up and down you meant the sine waves. So the spectrum would be a series of lines. I do know what a sine wave is, and mocking me pretending to talk to a baby is not going to help the image you have made of yourself. If I think that I even wrote to you to express my solidarity wrt troll attacks... And then you come up with "A sine wave is a transient signal". When it starts and ends, yeah, otherwise it is static.

I constantly speak of how the signal looks in the spectrum (the Fourier space) and then you come up with this. Pathetic.

You talk about transient signals but dont want to talk about them in the time domain. OK. A sine wave is a constantly changing signal. Im trying to be respectful but you are arguing based on fundamental lack of understanding.

Im not going to let this thread get derailed further so I will desist.

 

[JimB]

...
What do you think 32 tones all going up and down in amplitude at different rates is doing?
...

Any chance of seeing a bit of a screen grab of what a typical wave form is like for these signals? Of course, it is varying with time. Can one get a good idea of the range of variations seen in one screen? That is, can you capture enough time in a screen or two, with adequate resolution, to get a sense of the range of 'shapes' it has?

 

[mocenigo]

You can say you are professor, scientist all you want. You lack critical thinking and/or lack required related knowledge.

My g-d, this is a place full of mental people. I just asked for a proof that passing those tests are sufficient to prove faithful reproduction of all signals. Just one paper. No, I get a barrage of "you do not understand signal processing" with no arguments.

Calm down and explain. Because I haven't found any valid argument, unless one assumes that the behaviour of physical devices is somehow ideal. Which you should be able to admit, it is a bit of a loop. I am sincerely ready to learn, but curiously nobody has provided the material.

Think about signal processing. Think human auditory system as a filter. Think about how actually time domain and frequency domain react. 32 tones have to all beat to each other in time domain. The tones themselves are static in frequency domain. You can certainly add a sweeping signal at a higher frequency as well but that wouldn't change things. Think about control theory how DS work, how the stability realized, the frequency of 20khz comparing to the operating frequency of dacs. This just can go on and on and on. You ask those questions and think that way and saying who you are makes me feel really really weird.

 

[March Audio]

Any chance of seeing a bit of a screen grab of what a typical wave form is like for these signals? Of course, it is varying with time. Can one get a good idea of the range of variations seen in one screen?

should be easy

 

[JohnYang1997]

My g-d, this is a place full of mental people. I just asked for a proof that passing those tests are sufficient to prove faithful reproduction of all signals. Just one paper. No, I get a barrage of "you do not understand signal processing" with no arguments.

Calm down and explain. Because I haven't found any valid argument, unless one assumes that the behaviour of physical devices is somehow ideal. Which you should be able to admit, it is a bit of a loop. I am sincerely ready to learn, but curiously nobody has provided the material.

You said you are willing you learn but gave us the feeling you know everything?? No.

On the topic of transients, think about sinc function, think about band limited system, how the signal behaves in such conditions. What's the ideal output?

 

[JohnYang1997]

My g-d, this is a place full of mental people. I just asked for a proof that passing those tests are sufficient to prove faithful reproduction of all signals. Just one paper. No, I get a barrage of "you do not understand signal processing" with no arguments.

Calm down and explain. Because I haven't found any valid argument, unless one assumes that the behaviour of physical devices is somehow ideal. Which you should be able to admit, it is a bit of a loop. I am sincerely ready to learn, but curiously nobody has provided the material.

Also you quote the wrong phrase of mine. I never said you don't understand signal processing. I'm thinking of either you lack the knowledge or you lack the critical thinking. Those "think about"s are just directing you to find out the answer. If you know what you are talking about, you will get the answer very quickly.