Ok, just a warning... I'm an amateur engineer... I do things as a hobby (computer programmer by trade) Anyways, Here's what I'm doing: I'm trying to mod a guitar cabinet with LED lights that pulse with the music. I want to power it from the signal that comes into the speakers from the power amp, so I don't have to worry about plugging anything else in. Also, I'd like to use a potentiometer of some sort so I can adjust how loud of a signal triggers the lights. The goal is to get the lights to fade as the guitar gets quieter. The signal coming from the power amp is 70v 500 watts. Using an LED calculator, it seems I can make a 1x21 array with 70v input using a 39 ohm 1/4 watt resistor. My question is: If I try to push 70v 500 watts at a 39ohm 1/4 watt resistor, am I going to melt it's face off? :P I've never worked with anything bigger than normal 12v. Also, how would I wire up the potentiometer? Or if there's a better way of handling this, I'm all ears... I'm a total noob at this stuff. Thanks!