SV: Re: [sdiy] midi optocouplers

[Grant Richter]

>
> You could just tie the synth ground to one side of the AC line (on
> 120V)... its incredibly
> risky and stupid. I did it once to drive some theatre marqee lights.
>

May you should mention that you tied the frame to neutral.

The three wires to an US wall socket are:

Hot - current carrying 117VAC power wire - supposed to be black,  
don't trust color codes, use a meter.
Neutral - current carrying local ground - supposed to be white, don't  
trust color codes, use a meter.
Ground - non-current carrying local ground - supposed to be green. ditto

It is a good idea to verify that your electronic music studio wall  
sockets are wired correctly.
I have seen strange things happen when neutral and hot are reversed.
Even on transformer isolated equipment.

Some guitar amps have a switch and a cap that ties to the AC line.
Supposed to reduce hum, but mostly shocks people when they touch a  
grounded mic.


"Those who are not Socialist in their twenties, have no heart, those  
who are stilll Socialist in their thirties, have no brains" - George  
Bernard Shaw