Can I use the L and R pins and the 3.5mm audiojack at the same time without adding external circuitry? I’d like to use the 3.5mm jack to feed a sound system, and the L&R points for feeding a sound-reactuve pixel application on the Arduino. Is the board already designed to let you use both at the same time? Thx.
That should be OK.
The pads on the edge of the board are connected in parallel with the 3.5mm jack so both will get the same output. Just make sure you don’t connect too low impedance loads or your volume may drop off, but from what you’re describing, I think you will be fine.