Switched 12v wire color?

[Noizemaker]

Been googling, all I keep finding is "just use a multimeter and check". Before I start poking holes in my insulation, and doing contortions with my back under the dash, I'd rather just ask.

Need switched 12v that works anytime the car is running, doesn't need to be hot while cranking. Need it for the remote power-on wire for my amplifier. What color am I looking for? I guess I could tie in at the wiper motor, but I'm trying to avoid crossing through the firewall just to pick up my switched source. Is there one I can grab behind the radio? What color is it?

Car's a 64 Valiant. Anyone got a lead for me?

 

[MILO]

Pull your fuse box out and take the plastic cover of the back there will be a extra hot fused male connector to use

 

[Noizemaker]

And it's only hot when the key is on?! Awesome! Thank you!