Sigh. Looks like two of my pedals fried....

[slacker]

I assume the comp has some sort of ICs in it, opamps or whatever. AC will almost certainly have damaged or killed them.

[pappasmurfsharem]

I assume the comp has some sort of ICs in it, opamps or whatever. AC will almost certainly have damaged or killed them.

Yes unfortunately a CA3080.

So can I just take a 1N4001 and put it in series with the 9v supply? Any benefit with a 1N4007?

[slacker]

Yes a diode in series protects against connecting reverse polarity DC or AC, only disadvantage is you lose about half a volt or so.
Any 1N4000 type will do the job no advantage using a 7 over a 1.

[R.G.]

The appearance of 9Vac pedal power supplies is a profoundly bad situation. Series protection is the only good way to keep this from frying a pedal, and remarkably few commercial or DIY pedals have series protection.

The 1N5818/19/20 series of 1A Shottky diodes as mentioned earlier is a good start, as they'll only lose you about half a volt at the voltages most pedals run at. Doing better than that generally requires an active device.

I posted one way to do that back in 1999: http://www.geofex.com/article_folders/mosswitch/mosswitch.htm

This uses a P-channel MOSFET to turn on the voltage and its reverse diode to turn it off. You need the P-MOSFET, a resistor, and (usually) a gate protection zener. The only real disadvantages to this are the added complexity of adding a TO-92, a resistor, and a zener, and the cost, which is mostly the $0.40 to $1.00 a suitable P-MOSFET costs. You can do much the same with a bipolar, http://www.geofex.com/article_folders/cheapgoodprot.htm, but this doesn't do as well against AC adapters as it does DC adapters.