ESD, was : RE: [sdiy] midi optocoupler isolation voltage?

[Neil Johnson]

> Often Pin 2 of MIDI In is connected to ground via a capacitor. I've
> seen this on Yamaha and Roland devices.

I guess if it offers sufficient impedance to 50/60Hz to prevent a ground
loop than it _could_ help, but then _technically_ it would not be a MIDI
port as it would violate the spec !!

I'm always wary of gear with switcher power supplies, often having no
mains ground connection (like my W30 did).  The leakage current through
the smoothing caps is enough to give you a _very_ mild tingle if you run
your fingers over any metal surface (and enough to light up a neon
screwdriver!).  Fitting a mains earth stops this, but now you have to be
careful about earthing.

Ho hum, as it were...

Neil

--
Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
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