Hi @tedsmith Were you ever able to discuss JA’s jitter measurements with him? Specifically his comments: "I obtained anomalous results when I tested the PS Audio DirectStream’s rejection of wordclock jitter. Fig.13 shows a narrowband analysis of the processor’s output while it decoded 16-bit J-Te…

There are multiple things going on. When JA did the measurements he was using DS software that was measurably noisier than current software and that had some low level distortions. (He remeasured it again later https://www.stereophile.com/content/new-firmware-measurements ) Anyway in his original …

All black magic to me, although I love reading about this stuff. Another presentation of jitter measurements that I’ve seen reported (not DS, something else) are shown below. Apparently the thickness of the trace is due to jitter (so, the thinner the better). [59] [52] And another using a noise …

Great stuff Ted. Yes I did see JA did newer measurements but he didn’t re-do the jitter measurements, hence my question here. Thanks for the detailed reply. Great reason/s (in detail) for everyone to switch to TOSlink with your DACs… :slight_smile:

I should have said that you shouldn’t compare my J-Test plots to other devices, my scope doesn’t have the range I would need for doing a the job properly so my test signal is lower than it should be. But it has the values changing by the requisite least significant bit at the correct rate so the le…

Thanks again @tedsmith I saw in the other thread you mentioned you mostly work from home (>1000 miles away from PS Audio HQ) So do you have all the measurement gear that you need at home? Or do you have PS Audio do some measurements, with gear that you don’t have at home? I imagine PS Audio have …

PS Audio has multiple Audio Precisions - they can do great measurement of most things. I have an 8 bit 250MHz scope and a low noise 16 bit 5 MHz scope, both can do averaging to get about another 4 bits of effective precision or use FFTs and averaging to get more. Usually I can get close to the Aud…

[image] tedsmith: I sure wouldn’t mind a great 1Gig scope so I could do jitter measurements, etc. but they are extremely expensive. Long term ‘side project’ to build your own? :slight_smile: Or just get Paul to buy one !

Ted: Pal up with this guy… it’s like bullet time in the matrix! :smiley: I timestamped it to ~40mins – showing squarewave leading edges 10ps per division in realtime! Those high end scopes are insane! 110GHz/256GS/s

" The 110GHz 4-channel variant of the UXR-Series oscilloscope has an MSRP of $1.3 Million US dollars."

[image] tedsmith: The jitter I talk about is the jitter and noise generated by the FPGA, power supplies, etc. that leaks thru the reclocker or into the analog output. That noise swamps any jitter influence. Hi again Ted, regarded what I’ve quoted here - is this basically RF and ground leakage…

Yes, but perhaps a better way to put it is that the input jitter is suppressed to a point that other things matter more.

Stereophile's DS jitter measurements

Audio Components DACs

JMK November 12, 2018, 3:38am 17

The HMDI / I2S input in my DSJ sounds amazing in comparison to the USB input.

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Stereophile's DS jitter measurements

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