It will not show, ARTA just using dual channel which is R in differential mode.
The pervious link has information on the difference between single and dual channel measurements.
I guess you mean "difference between L and R", as the 0404 inputs aren't differential/balanced on their own?
As far as I can understand, that measurement set-up defines "dual channel" as a "difference between measurement channel and reference channel", but as the circuit isn't DC coupled, the measurements at very low frequencies will be misleading (what is the difference between nothing and nothing?).
In any case the measurement system seems to be the limiting factor (as mentioned, the nc400 is DC coupled).
I'm ok to do a comparison measurement.
What I can think of now is using my M-Audio USB Transit to perform a test on my own amp, then measure again using EMU 0404
Why not just measure a straight wire?
Its will burn off the ADC as the Amp output voltage are high, in which I have already killed 2 USB audio devices before with heavy smoke.
When I measured the NCore, I increased the output voltage too high that the 10W 8ohm resistor overheated that it melted and burn off the PCB inside the Jig.
ARTA's differential and EMU 0404 differential is not the same thing, ARTA's differential uses the reference channel to compensate the difference.
For DC Coupling, its good to have maybe in my future jig. But I believe the NCore should not have any DC Leakage, as my multi-meter shows 0V(DC), after I measure AC to 1W/8Ohms
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Oh ok, its Loopback test.
But you can find results of the EMU 0404 loopback test results online.
But here are mine, without spectrum analysis. All running in Single Channel
Left vs Right
An externally hosted image should be here but it was not working when we last tested it.
Left Channel Dist
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Right Channel Dist
An externally hosted image should be here but it was not working when we last tested it.
Thanks!
Shows that the frequency responses are pretty much exactly the same, except for a difference in gain.
Here the difference is again pretty small.
So, as I have implied, the nc400 is actually better than your test setup - what you are measuring is mostly your own measurement system.
Ok why not run measurements on your own NCore and probably we can do some comparison?
Well, I did, and realized the situation was the same as with your setup - the nc400 was better than my measurement system. I will at some point try to get access to a more sophisticated measurement system - even my spectrum analyzer is starting to show it's age.
NC400 noise floor
Has anyone tried to measure noise floor of NC400?
I'm not able to confirm datasheet value 24uV (eta. -92dBV RMS).
My measurements of NCore with shorted input on balanced input of ESI Juli@ gives -88.3dBV RMS (at 44.1kHz) that is 38uV. Noise floor of shorted ESI Juli@ is -90.2dBV RMS, so there is some margin.
Attaching some graphs:
http://mr.ieero.com/pub/NC400/Juli@-NCore-shorted.png
http://mr.ieero.com/pub/NC400/Juli@-shorted.png
Has anyone tried to measure noise floor of NC400?
I'm not able to confirm datasheet value 24uV (eta. -92dBV RMS).
My measurements of NCore with shorted input on balanced input of ESI Juli@ gives -88.3dBV RMS (at 44.1kHz) that is 38uV. Noise floor of shorted ESI Juli@ is -90.2dBV RMS, so there is some margin.
Attaching some graphs:
http://mr.ieero.com/pub/NC400/Juli@-NCore-shorted.png
http://mr.ieero.com/pub/NC400/Juli@-shorted.png
Can someone explain how distorsion is measured? is it comparing input and output in discrete parts or as a larger whole? dont know how to explain what I mean...
The thing I am after is that the only thing I think is not "perfect" with my NCores, is how sounds decays. Feels like the end of a sound is chopped of. maybe thats the secret why the sound is so "clear"?
If a amplifier is loosing some decay of sounds, will that be shown as distorsion in a distorsion-measurement? That is really my question.
The thing I am after is that the only thing I think is not "perfect" with my NCores, is how sounds decays. Feels like the end of a sound is chopped of. maybe thats the secret why the sound is so "clear"?
If a amplifier is loosing some decay of sounds, will that be shown as distorsion in a distorsion-measurement? That is really my question.
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The typical method is by feeding the amp a sine wave, and watching how much signals show up at frequencies that are harmonics of that sine wave. It is a steady-state measurement where time and decay doesn't play any role.
"Chopped off"? After some delay time, or below a certain level?
Regarding the "chopped decays". I've also observed some difference between top linear amplifier and the NCore. To me it was like "missing" or "reduced" ambient sounds in the recording, but it was just feeling and not properly performed blind test. Another person who uses several NCore in his home system has described difference against the same amplifier as "the lack of natural reverberation and spectral envelope of instruments/voices".
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