Arduino MIDI Shield Audio Out Grounding?

[samp]

Hi,

I've just bought a LinkSprite MIDI shield(see photos) to work with an Arduino Uno and am having trouble hooking up a 3.5mm audio out socket. The audio should be coming from pin 9 from the MIDI shield, but the shield is using the ground pin from the Uno.

The Uno is receiving MIDI signals but I can't figure out how to send it to a speaker. Is it possible to use the ground from something else?

Thanks for any help!

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[Grumble]

Standard a Midi input is isolated from the rest of the circuit, just like this Midi device.
The outputs are NOT isolated from the circuit (Arduino et al) but that should pose no problem.
Using pin 9 from the Arduino as an analog output I suppose You use some program that outputs a PWM signal on pin 9?
In that case you need some additional circuitry in the form of (minimal) some capacitors and a resistor and you can surely use the GND pins of the Arduino to ground the audio signal..
Check THIS out.

[gdavis]

The shield makes many ground pins available on the headers - P7, P9 and P10 are all ground (they are all connected to the ground pins of the Arduino through the shields ground plane).

See the schematic on their web page.

[MusicMan11712]

[removed due to personal reasons]

[samp]

Thanks for the help. I'm running the Mozzi library out of pin 9 and can use P7 as ground. Tip top!

Here's the schematics:
https://s3.amazonaws.com/linksprite/Shields/MIDI/MIDI_Shield_sch.pdf

Now I have to figure out midi polyphony from Mozzi.

Cheers