[sdiy] Midi 3.5mm cable

[rsdio at audiobanshee.com]

On Aug 25, 2016, at 12:49 AM, Vladimir Pantelic <vladoman at gmail.com> wrote:
> On 25.08.2016 09:37, rsdio at audiobanshee.com wrote:
>> 
>> I retract my statement suggesting that 3.5mm is better because of its size. I'm now thinking one of the other options would be better.
> 
> 3.5mm will work if you use a stereo jack, then you can use the sleeve
> pin for chassis ground and tip and ring for the actual MIDI current loop.
> 
> no?

No.

That's my whole point: MIDI is designed so that the output jack ground the cable for shielding, but the input jack does not connect that pin. Unfortunately, a stereo jack will ground the Sleeve if it's mounted to a metal case or a metal face plate. Of course, this isn't a problem for plastic products, of which there are many examples, but synth modules would not enjoy the isolated ground that Classic MIDI is designed with.

You also can't simply move the ground to another pin, because none of the MIDI signals can connect to chassis.

If you want to stick to 3.5mm, you'd need the new 4-conductor jacks that are common with mobile phones that combine a mic and headphones with transport controls. Then you'd be able to keep the Sleeve and Chassis ground separated.

Brian