Hello, so this is my first time posting here mainly because of my unique situation. I own a "non-amped" 1996 Cadillac Deville and since I consider it to be something to be kept in pristine condition, I didn't want to take out the factory radio or splice any wires while upgrading the stereo. So my solution was this: I bought a line-output converter and a class-T amplifier (links to the specific products below). I re-routed the speaker wires that go directly to the rear deck speakers and hooked them into the line-output converter, and from there to the Class-T amp, and from there to the speakers. The amp runs off 12V (which is mainly why I bought it) so I figured I could find an empty fuse spot on the trunk fuse box and hook the + power to there. The exact fuse spot I chose is called "AMP" and it's for the optional Bose amp, which I don't have.

So I hook it all up correctly, using a bolt holding the fuse box in place as the ground, and it works when I turn the key to "ACC" (or whatever it's called for the radio to turn on). But once I start the car, it works still for a second or two, then shuts off. No sound at all comes out of the rear speakers. After maybe 10-15 minutes it starts working again. This confuses me highly because I can't think of any reason why this would happen - it's not the radio, because the front speakers still work.

The amp stays on when the speakers go out, evident from the blue light that comes on when the amp is running.

So obviously my question is why this would happen?

Amplifier used is Pyle PFA300 90 Watt Class-T (http://www.pyleaudio.com/sku/PFA300/90-Watts-Class-T-Hi-Fi-Stereo-Amplifier-WAdapter)
Line-Output Converter used is Stinger (http://www.amazon.com/Stinger-SGN12-Fixed-Output-Converter/dp/B001JQ4MP8)