Reverse Polarity Protection AND Overvoltage Protection? Zener?

[Earthscum]

I built a pedal for a buddy (Zen workalike, RC4558D, more "TS" sound...) and it worked one night, he plugged in the next day and had nothing.

Long story short, the chip is fried. Obvious was the 4.5V measurement at pin 8, lol. Anyways, I suspect possibly 2 things, and want to get your thoughts on this.

Chalo tours with a prof. Blues band (http://www.blinddogsmokin.com/), and uses a Strat w/Afterburner => Wah => (Zen) => Delay => modded Boogie MKII. He uses a 1-spot from an on-board strip to power his effects. My only guesses are that he unplugged from the wall, causing a quick overvoltage from a spark gap, or somehow when he plugged in or unplugged from the wall that it may have caused a rev. or over voltage. Thoughts? Could the Afterburner sent a spike to the input on plugging in?

Now, could a 12.1V Zener take care of both problems, or should I incorporate something more? Should I be protecting the first amp's input with a reversed diode to ground?

[R.G.]

Can you do a sketch of how it's hooked up?

And I'm not familiar with a Strat Afterburner. Got a link?

[Earthscum]

Can you do a sketch of how it's hooked up?

This is basically what I built, but I used RC4558D, and different diodes for clipping. The switching is just the Millennium bypass with 2PDT. The bypassing still works just fine, the FET didn't get fried, if that helps.

ICYC, the 2SK117's make EXCELLENT switches for the Mill bypasses. Tayda sells the "GR" rating, which is higher current, perfect along with the ~-.5V VGS off. I haven't had a "bleeder" yet since I started using them.

And I'm not familiar with a Strat Afterburner. Got a link?

and uses a Strat w/Afterburner

http://www.guitarcenter.com/EMG-AB-AfterBurner-Pickup-Booster-Knob-101558401-i1398159.gc