Headphone Jack Question for Audio Build.

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I am finishing up an synthesizer project using the Teensy 3 Audio Board and a Teensy 3.6.

Currently I have a mono 1/4" jack soldered to the Line Out (Ground / Left). That works great.

However, I want to add a stereo jack so that users would have the opportunity to use headphones with the instrument. If I were to build a headphone out (Line Out | G / L / R), and someone were to accidentally plug a mono cable into that jack, thus shorting out Line Out Left to Ground, would that fry the any of the electronics?

Thanks so much!

Picture for reference.
According to the SGTL5000 datasheet, output impedance is ~320ohm, therefore I don't think the chip would be damaged. You could always add a resistor between the line outs & the jack, but if I were you I would add a dedicated headphone jack (line out is really not that loud with headphones)

Make sure you keep the grounds separated - see caution on silkscreen

Both LINE IN and LINE OUT on the Teensy Audio Board have DC blocking capacitors (in other words, they are AC coupled). This is common (and required) for every external audio input or output on any audio device you wil find.

Shorting an audio signal to ground (like when you stick a mono TS plug into a stereo TRS jack) is applying 0V to the Ring connection. But 0V is no different from driving +5V from a frequency perspective, they are both DC, and are both blocked by the coupling capacitor.

And as mentioned above, you cannot use LINE OUT to drive a pair of headphones directly. You will have to use an external headphone amplifier if you specifically want to take the LINE OUT signal and eventually feed headphones with that signal. Otherwise, use the existing headphone connection on the board, but be careful with it's virtual VGND and don't connect it to a real GND.
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