I have seen some equipment manuals which recommend a 20' max on MIDI cable 
runs, but, from experience, I've found this to be conservative. I've used 
100' MIDI cables with no glitches.  I think the limit may depend upon the 
devices used.  A MIDI controller pedal powered by a 300ma 9V wall wart power 
supply might not do the job as well as a MIDI patchbay running off a 1 amp 
12V supply.  I've seen an ad for a unit by Anatek which uses 2 MIDI to XLR 
adaptors and can be used up to 500' with microphone cables. 
--- Opus-CBCS 1.73a
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