I'm not real up on this stereo stuff so bear with me, okay, say you got a 200 watt head unit, 50wx4, and a 160watt amp, 40wx4, would hooking up the amp make a difference or would it just burn the amp up? Or would it put out 90w a channel?
What about when you install an aftermarket head unit into a car that has a factory amp, you not using RCA's to get signal to the amp, cause when I installed an aftermarket unit into my 89mark7 i didnt you the RCA's to get signal to the factory amp, is the internal amp in the H/U still bypassed?
a vehicle with a factory amp uses what's called "line level input" which is the speaker output so YES you use the amp in the HU ... BUT keep this is mind .. the output they claim is usually the PEAK power output which means you get this at the amps very best it may happen once and never again after that .. what you want to look for is RMS which is the consistent output of the amp ... so your HU that is 50WX4 is most likely only putting out 16Watts RMS X4 maybe a little more if it's a higher end audio source unit...