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Re: my previous posts. Below are are commeents in diyhi.org
sidiy wrote:
I don't know if a single pole filter can do the trick for delta-sigma DACs, even when talking about the AK4396... one trick is to evaluate the results of the change by listening to headphones, especially at low level signals...
---------------------------------------------------------------------Your advice to listen to the thing is good, that is what every designer should do, and it's part of the development process.
Most voltage output delta-sigmas already have an internal 100Khz lowpass filter, and some are already 2nd order.
A simple external 1st order RC above 100Khz will be enough in most cases, and in some cases you can even skip this.
These days, delta-sigma dacs (with integrated DF) are all 8x oversampling.An external 3rd order filter is too much of a too muchness, if the dac chip already has an internal second order lowpass.
Filteritis aguditis just kills the sound. But can improve the SNR specs, though. Looks good on paper...
Specs, specs...
_________________
Carlos Filipe"It's a matter of striking the notes at exactly the right moment". Bach (a low jitter guy).
Follow Ups:
The 1212 card uses CS4398 dac chips, not AKM which are used in 0404 pci/usb
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So, we have inbuilt dac filter; 3 pole filter giving -3dB at 48k for a 192k system. If this is not band limiting from 40k or so I don't know what is.Plenty of reviews on SACD systems point to 50k roll off as undesirable. Yes you can hear these filters.
You still haven't demonstrated to us exactly where this "extra" filter is located.And why exactly are you spending so much time and energy on this anyway? You don't even own the device and has never heard it. Why does it matter so much to you?
I mean look at you, you spent all that time culling posts from another forum, and they are not even relevant to the 1212M. The first post mentions AKM, and the 1212 doesn't use AKM. The second post mentions 3rd order filter, and yet measured results on the 1212M shows that it is NOT using a 3rd order filter.
So what exactly is the point of quoting them? Do you even have any clue what you are talking about?
And now you're talking about roll off on SACD. Again, what does this have anything to do with the 1212M?
nt
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