I havent installed an alpine. But all HU's that i have put in have a yellow wire that is connected to a constant battery source and a red wire that is connected to a turn on power source. Now depending on your vehicle (whether it is old or not) you should have all the leads needed to wire your aftermarket hu up from the factory location. And to make it even easier you should be able to find a wiring harness for your vehicle that will match the leads from your hu. the leads should be labled in the manual. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
well, if it has a v-drive internal amplifier...then it is "recommended" that you wire it directly to the battery for it to provide full power. If ur not even using the internal amp...i'm not on my 7894...then don't worry about it. my comps are powered by their own amp, so i didn't bother. peace