Audio port: physical damage protection?

[Hardware]

I would like to use the headphone jack on my optimus v as a signal generator for various experiments including but not limited to flyback transformers, induction coils, and other dirty fun things involving high voltage. Mostly I will use a darlington pair consisting of 1 2n3055 driving 4 parallel wired 2n3055's. My question is; how well protected is my droid's audio hardware? Should I use an opto-isolator even when I plan to run this at nearly 1GHZ if hardware allows? Any feedback is appreciated!(except the high voltage type)