Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: nyu notesfiles V1.1 4/1/84; site rocksvax.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!houxm!whuxl!whuxlm!akgua!sdcsvax!dcdwest!ittvax!decvax!genrad!panda!talcott!harvard!seismo!rochester!rocksvax!dave
From: dave@rocksvax.UUCP
Newsgroups: net.music.synth
Subject: Re: MIDI
Message-ID: <26500002@rocksvax.UUCP>
Date: Tue, 26-Feb-85 21:12:00 EST
Article-I.D.: rocksvax.26500002
Posted: Tue Feb 26 21:12:00 1985
Date-Received: Sun, 3-Mar-85 02:59:04 EST
References: <3416@alice.UUCP>
Lines: 17
Nf-ID: #R:alice:-341600:rocksvax:26500002:000:835
Nf-From: rocksvax!dave    Feb 26 21:12:00 1985

Opto-isolators are the best things to use when you want to electically
isolate signals.  Most musical equipment tends not to get grounded very
well and you can end up with a healthy current flow through the grounds
on your signal lines.  These lines tend to be small gauge and can easily
build up volts of ground loop messing up the signal, not to mention the
potential of electrocuting the musician, and/or frying the instrument.

While not strictly necessary a side benefit is it easily converts currents
to voltages and give you about 2000V of isolation in a little package.  You
could always use a plain op-amp as a current to voltage converter, but
I suspect that it costs the same  The opto way giving you as a bonus this
isolation benefit.

Dave

arpa: Sewhuk.HENR@Xerox.ARPA
uucp: {allegra,rochester,amd,sunybcs}!rocksvax!dave