Electrical Specification for MIDI

“Designers of personal computers are not generally audio engineers and apparently have not heard of ground loops. In fact, given the noisy fans and screaming disk drives that go into the PC, it is a wonder they can hear at all. All that noise forces some audio professionals keep the computer in a closet or another room. But the primary source of ground loop problems in PC audio is the PC soundcard MIDI interface.”

Electrical Specification for MIDI?

True, and audio guys are not electrical either, if one looks at the MIDI spec. The only ESD protection on those invertors is the 220 ohm resistor. Sure, it may help, but come on guys, you know someone is going to hit that MIDI connector with a 20KV static discharge. The poor gate is just waiting to get blown away. I’m also not entirely convinced that the optoisolators emitter is going to be thrilled with a big whack either. At least its got a resistor for current limiting, and the reverse biased 1N914 will keep errant signals from bloging away the emitter, but that doesn’t help the ESD world one bit.

Now, should you want to control your Christmas lights via MIDI, a show control spec is published on line here. Its not guarantee of compatibility, but its at least a good starting point.