Hi Alain!

SOtM have a new driver:

http://sotm-audio.com/english/bbs/board.php?bo_table=notice&wr_id=37


Tore

Hi there Bob - warm welcome here.

(please notice that your post plus response(s) to it are candidate to move to another board later - probably Support or maybe Chatter)

First off, you don't want to know how many people with a fair amount of more hindrance than you got all going - but it may require some help which is available here (like you apparently contacted Juan in private). Otherwise we at Phasure have a PC ready for you - get it out of the box, hook up your NOS1, start XXHighEnd and press Play. But this NOT assumed :

Many people go crazily far with the "noise" and such, and you know what ? I myself am even not amongst them. That is, not this PC noise. Software impeded yes, but that's what XXHighEnd is for from top to bottom.
... which does not tell that getting those last pieces of noise out of the way will not improve ...

I will try to give you one example of how noise even "goes through light" - which hopefully explains :

Your zeros and ones - transported from PC to DAC - is essentially an analog signal, with a fixed amount of plus voltage for the ones and (close to) zero for the zeroes. The sequence of the zeros and ones create "data" as such, which is binary code but further not important for our story. The fact that this is just an analog signal is though;

When the signal goes to plus, something has to happen (like interpreting it *is* a plus or better : a one). This going to plus goes with a certain "ramp up" hence steepness. So, not veryically straight up, but with a slope (which is as steep as possible, but inifinitely steep is not possible in electornics). Now :

The devices which interpret this 1-0-1-0 sequence, have a threshold for when a 1 becomes a 1. So, say that the peak value in voltage of this signal is 1.2, then at 0.8 and more it will be interpreted as a one. Under that it should be zero. But now comes the trickery part :

If this would be a completely noiseless signal, the moment a zero becomes a one (or the other way around) would be completely fixed in time. With this I mean : from the one part of the signal to the other, with a virtual evenly space between the "data", from one part to the other goes in a fixed time (think 0-0-0-0 or 1-1-1-1 or 1-0-1-1 etc. and the "-'" parts being this fixed time). However :
When there is noise on the signal, and notice that noise is a "wave" within itself, it disturbes this fixed time in between these parts, and this "jittery" property of the data is, well, jitter !
So, this noise-wave on the signal makes the signal wobble, and because of that the detection of a one can come early or late (detection of a zero just the same).

The means our audio samples are put out from a DAC works via above described means (a voltage goes up -> put out the sample), and is thus subject to jitter once noise is in the signal (there are more sources for jitter, but since you wondered about noise, this is our subject today).

Once the samples are not put out evenly spaced in time, this is audible. Think about the wow and/or flutter of a turn table, and the effect is exactly the same, only it goes 10s of thousands of times faster. Now you can imagine how digital can sound nasty - just envision the "judder" of a turn table to be there infinitely more fast.

So, I started out with your "noise through light", and here is your answer :
The means at the DAC end to "convert" light to voltage again, is a noise source by itself.
The remainder was explained above ...

And for the non-light connections : Any noise which comes from the computer travelling along with the data, implies the same noise at the DAC end.

Easy ? I think so. Once someone explains it, on which I hopefully succeeded somewhat !

Kind regards,
Peter

Where to buy :

http://www.360searchbuy.com/product/9221283886/%22Assi%22-Skittles-PC-HiFi+power+clean+sound+filter+cards+%28%3Cspan+class%3DH%3EAXF+%3C+span%3E-%3Cspan+class%3DH%3E104+%3C+span%3E%29

Don't ask me whether I'll ever receive something. Needs Mastercard, Visa or another obscure card.
Count on another 4 USD or so for shipping and credit card administration fee.

This is the cheapest :

http://www.360searchbuy.com/product/14884879283/Xsound-Skittles-PC-HiFi+purification+filter+the+power+supply+card+%28%3Cspan+class%3DH%3EAXF+%3C+span%3E-%3Cspan+class%3DH%3E104+%3C+span%3E%29

Don't blame me for anything !
Peter