[sdiy] Odp: MIDI on Cat6

[Roman]

MIDI port impedance is 450-500 ohm, while characteristic impedance of CAT6 is 100 ohm, so it will be not matched big time. Assuming typical rise/fall times of 10ns compared to 200ns return delay of that line you may notice aparent effects of non-terminated trasmission line, like stepped waveform. It should all settle within 1-2us so regular opto+uart receiver should not even notice.  Think also about radio transmission that will leak out from MIDI line on junctions no matter what you do to that metal tubing and cases.  I would auggest adding some RF filters at both ends of the cable, like those 3-terminal thingies found sometimes in well designed equipment on every i/o port. They do much better job than simple ferrite beads.  And above all - no commercially available MIDI patchcord will ever be half as good as regular CAT6 cable.   Roman   PS. it's so sad to see that most of SDIY list traffic is related to occasional drop of traffic on AH list...   Dnia 19 września 2016 19:29 Dave Magnuson <abide at dmdrafting.com> napisał(a):
                  Hi All,     I’m wiring up some wall jacks in my studio so I can MIDI and audio from one side of the room to the other without a bunch of cables lying on the floor     My question is:   Do you think it’s safe to use Cat6 cable for MIDI?  Cat6 itself isn’t shielded, but it will be routed entirely in metallic tubing and metal boxes, all of which will be grounded.    Do you think there would be a high likelihood of cross-talk between twisted pairs within the Cat6 cable itself?        The runs are about 20 feet (3 meters) with 2 sets of MIDI cables per conduit.  I will likely wire up all 5 conductors on each end so I can use it for din sync, too.  I’m not so concerned about MIDI bleeding into the audio because they run in separate metal conduits, and likewise with nearby power wiring.     Anyone ever tried something similar?   If I had star quad I’d just use that, but would prefer not to buy a spool if I don’t need to.     Thanks!     Dave Magnuson        ______________________________  Synth-diy mailing list   Synth-diy at dropmix.xs4all.nl  dropmix.xs4all.nl dropmix.xs4all.nl
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