In dacs you can choose between sharp filter slow filter etc. That's them that put the ultrasonic far away so that it can be filtered more easily with analog low pass filter If there is still ultrasonics noise and distortion it's a failure of the filter of the dac (digital filter or analog filter)
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Review and Measurements of New Topping D50s DAC
- Thread starter amirm
- Start date
Anyway without the tube buffer dacs put garbage in the ultrasonic that is hidden on measurements.
Ok that means the other things i said are right
No. But you do seem more interested in eristics than acoustics.
So to you it's not bad to have ultrasonic garbage and if tests don't show it it's not important??
It's crazy.
The goal of the filter in the dac is to filter.
If there is still garbage that mean it doesn't filter good.
If no test show if the filter is good or not it's a big mistake.
If you think proper filtering is not important well it's sure we better stop talking. I get my answers.
This ultrasonic garbage can interact with digital amps that have hf modulations. Or with high bandwidth amp.
It's always better to filter properly the ultrasonic garbage.
If no test shows it we should find one because it's important.
But you seams scared to get not so good measurements and that would fail all the marketing of dacs.
@amirm thanks for your honesty to show us that those ultrasonics are hidden on tests.
It's crazy.
The goal of the filter in the dac is to filter.
If there is still garbage that mean it doesn't filter good.
If no test show if the filter is good or not it's a big mistake.
If you think proper filtering is not important well it's sure we better stop talking. I get my answers.
This ultrasonic garbage can interact with digital amps that have hf modulations. Or with high bandwidth amp.
It's always better to filter properly the ultrasonic garbage.
If no test shows it we should find one because it's important.
But you seams scared to get not so good measurements and that would fail all the marketing of dacs.
@amirm thanks for your honesty to show us that those ultrasonics are hidden on tests.
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- Feb 5, 2019
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From the way he writes, I guess Calexico is french, like me.
We, french people, like to ask questions instead of reading articles.
If someone could stop 5 minutes & explain why it is ok to "hide" the ultranoise, everybody would be happy!
I am also interested.
As for me, what I understand is that filters can filter the fundamentals, but can't filter harmonics, and that's why you end up with ultrasonic noise anyway. Is that right?
We, french people, like to ask questions instead of reading articles.
If someone could stop 5 minutes & explain why it is ok to "hide" the ultranoise, everybody would be happy!
I am also interested.
As for me, what I understand is that filters can filter the fundamentals, but can't filter harmonics, and that's why you end up with ultrasonic noise anyway. Is that right?
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OP
- Thread Starter
- #91
The purpose of a filter in a DAC is to properly reconstruct the digital signal into analog. Its job is NOT to remove noise/distortion that bleeds into the DAC due to other reasons. A perfect reconstruction in a DAC therefore can still leave plenty of ultrasonic noise and distortion.
In my analyzer, I can choose to filter the incoming signal using any filter I choose. By default I use 22.4 kHz since that is a standard filter in my analyzer and is a bit above hearing range. So those results as seen in the dashboard are representative of what is audibly relevant.
In the THD+N vs Frequency by necessity I need to increase the bandwidth to catch the harmonic distortion (H in THD) of higher frequencies. For example the fourth harmonic of 20 kHz will be 80 kHz.
It is true that DACs with junk in ultrasonics are deviating from ideal. Our highest performance DACs are very clean there. Lower ones in budget categories tend to not be as well although these are generalizations.
The ultrasonic tone in D50s is about -80 dB. Even if that were in audible band, you wouldn't hear it unless it is in mid frequencies. At 28 Khz or whatever, it is just not an audible concern although I personally wish it was not there.
OP
- Thread Starter
- #92
A filter certainly can do that as my analyzer's input filter shows. THe issue is as I explained: there are other stages past the DAC (chip) filter that are non-linear and can generate harmonic distortion. And the filter in the DAC is not having infinite attenuation so it lets some harmonics to bleed through.
In this case, the 28 kHz tone is actually NOT a harmonic distortion (the signal itself is at 20 kHz). It is some kind of spurious tone for which I don't have an explanation as to its source.
OP
- Thread Starter
- #93
This is true but the ultrasonics here are at -80 dB. Intermodulation occurs at much lower level than the signal, making them very small in amplitude (i.e. much smaller than -80 dB). But yes, it is good to not have them.
restorer-john
Grand Contributor
The member ignore function is more trouble than it is worth. The entire structure of a decent disagreement between members gets broken. I see SIY arguing with himself or saying things that make me think he's been drinking, again.
lolololThe member ignore function is more trouble than it is worth. The entire structure of a decent disagreement between members gets broken. I see SIY arguing with himself or saying things that make me think he's been drinking, again.
restorer-john
Grand Contributor
And I thought you and SIY were about to duke it out.
restorer-john
Grand Contributor
Are you positive you used 44.1k sampling? 28k suspiciously looks like an image for 20k input on 48k sampling.
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