Hey Nick,
Yeah, nice eh ?
Ps I took a look at the spec for the TS8100, what a great bit of kit, I can now add scope envy to the FFT analyser envy I already had haha !
Envy ? sheer obsession ! Well, I think you know how long I have been trying to find something suitable (which is all related to $$$$$ of course). And then to think that I sort of blindly ordered this one from some obscure looking Korean company expecting a brick in the box ... But it went all right.
TS-8100
0 btw.
Although I don’t have anything line the scope resolution you have with your TS8100, amplitude jitter and audio clock edge smearing and smearing of eye diagrams can be seen hear to some degree even on my modest scope.
Nah Nick, I don't think so. But the problem is, once the sampling speed is high enough this starts to
look like that. But all what happens is that the sampling itself (and/or the math behind it) is jittery and that's what you see. Just do the math on what sampling speed it takes for analogue already to enable the visibility of 210ps of jitter. And when you are as far as that (will give "buyable" results) then know that the bandwidth (still in order) is too low to get any decent upright rise out if it (like you see in my screen shots something towards 90 degrees). So instead you'll have a triangle sine like flat shape and that won't allow time domain jitter to be seen.
Make that a digital sampling scope and not even 40GHz will bring you close.
But ok.
Reading your post above and your other resent post on the NOS1 upgrade, if I have understood them correctly you have applied a number of really important changes to the audio clock setup since the upgrades to my NOS1 were applied a couple of months ago. This is moth watering
Well yes. And for other people's information : that few months ago I was as far as finally trying the isolation itself just to see what it would bring with small PCBs for that which I had (let) made and which were in the house for maybe 6 months already. So these were only there to test it, not to really apply it. So, they worked which wasn't all *that* exciting (but with my expectation that there could be a ground-potential-looping problem just because of the potential difference on either side which had to go somewhere (radiation !) but that problem didn't happen and actually it sounded quite OK as well. But as I told Nick, now we could be guaranteed to have jitter just because the isolation implies that. But it was just a trial in itself ...
With the boards and wires all over the place with a next attempt because I got that "other" idea of how to possibly apply this to the existing NOS1 while nothing was intended for that, that worked in one go and all what remained what now designing something that could be piggy-bagged to the existing NOS1; a challenge in itself because of the available space from all directions. But in the end it all worked out.
Right at this moment the only thing left is the wiring between USB and DAC in a nice decent fashion.
Oh, might someone know a source for 2.5-3.5 mm internal diameter cotton braided sleeve ... (and I mean one which ships and delivers within 2-3 days instead of possible weeks from the US).
The tuned results you are getting get in your last three graphs above look great, is the trace being taken from the directly from the bit clock feed to the DAC chips ?
Not sure whether you really intended to refer to the last
three graphs, but yes. Or almost yes, because that couldn't be done directly for the best result without additional measurement wires. Point : The best result will not look better (scope limit). So if you look closely you see that I sneaked in a Word Clock shot (watch the frequencies) and this is all in advance of where the real stuff happens - but still good enough and thus knowing that the scope is not able to show better anyway.
important changes to the audio clock setup since the upgrades to my NOS1
On this one and especially for you (because you will be able to envision it from your situation as of now) :
The oscillators now are on one of these new PCBs ...
Hey Nick, as you will understand you were one of the great motivators for this. I mean, no matter what we all could find or try to reason for this USB sh*t, in my opinion this was not exactly under our control, no matter we could audibly improve on it. So that's why. Or maybe that's why with some priority now, because of course I have always been thinking about THE solution.
Thank you ...
Peter
