Alright, ran some tests on the Touch to see how well it works doing transport duty! 14362
Setup: Touch with EDO firmware off the app gallery installed. For the sake of clarity, when I indicate a test was run in "EDO mode", this means it's the digital only mode, otherwise I'm referring to the default "digital + analogue" mode. The Touch was connected by ethernet to the basement music server --> either TosLink or coax out --> ASUS Xonar Essence 1 DAC --> XLR cables --> E-MU 0404 USB for measurement. As previously measured, the balanced XLR output from the Essence One has so far given me the best electrical noise suppression and lowest noise floor, the Touch was used as the digital transport for this system. I then played the RightMark calibration, and test tones off the Touch and measured the analogue out from the Essence 1. About the digital cables: TosLink - cheap "VITonet" labelled plastic fibre cable - no idea where I got this, if I bought it, would likely be <$10 at local supplies store. Pretty thin and flimsy looking but gives a good tight connection with the ends. Coaxial - this gave me an opportunity to try a simple unshielded 3' stereo audio RCA cable (zip chord that I never used supplied with an old DVD player! forget any impedance matching or electrical shielding) vs. an actual shielded 6' coaxial cable "Acoustic Research Pro Series" I bought 10 years ago for ~$20. First off, 16/44: 14359 Nothing to see here! Essentially perfect measurements... The 1st column is just the audio played to the Essence 1 through USB 2. Whether I used TosLink, cheap RCA, actual coaxial to connect to the Essence 1 from the Touch did not matter. Now, 24/96 (standard "digital + analogue" mode): 14360 Hmmm, not unexpectedly, the "RCA as coaxial" is the stand out here. Slightly reduced noise floor (~1 dB), reduced dynamic range (~2 dB), mildly worse stereo crosstalk. How about 24/96 in "EDO mode" with the analogue output turned off? 14361 Essentially the same as the standard mode. It appears that turning off the analogue output circuitry (or at least silencing it) does not affect the test results in any meaningful way. Again, the RCA cable performance is inferior to a proper shielded coaxial cable. However one has to realize that at this level of performance, the difference is really so minor that it's unlikely anyone would be able to tell a difference from listening! To give you an idea, here's the THD plot, notice how little difference there is with the RCA cable (cyan) just rising over the others like around the 5-10kHz range. 14363 Conclusion so far: 1. 16/44 performance is beyond reproach according to these tests. 2. 24/96 performance likewise is excellent. Starting to see the limitations of an unshielded cable connected to the coaxial SPDIF but even in such an extreme situation, the rise in noise floor likely inaudible. Later, I'll add the "EDO" 24/192 measurements! +-------------------------------------------------------------------+ |Filename: 24-96_THD.jpg | |Download: http://forums.slimdevices.com/attachment.php?attachmentid=14363| +-------------------------------------------------------------------+ ------------------------------------------------------------------------ Archimago's Profile: http://forums.slimdevices.com/member.php?userid=2207 View this thread: http://forums.slimdevices.com/showthread.php?t=97950 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/audiophiles
