# Speakers powered by head unit or amp on standard factory system?



## fredmr (Dec 22, 2011)

Hey guys - I've been trying to educate myself on this system before I make it my own, but haven't found a ton of information searching. 

I know there are users who have installed aftermarket headunits with all the necessary Metra accessories (I've ordered these), but I just wanted to verify that all of the systems use externally mounted factory amps. I know the Pioneer system does - but was not sure about the standard system. Because people are able to replace the head unit and not have any problems.... I'm assuming factory speakers are powered by a factory amp so simply replacing the head unit wont be an issue - but just wanted to confirm this, because I'd hate to eff up a $1,000 head unit. 

I will be adding my own speakers/amps in the coming weeks, but haven't made a decision on the speakers I want yet, and I know the moment I get the head unit I'm not going to be able to resist installing/waiting for the rest. 

Thanks!


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## fredmr (Dec 22, 2011)

Answered my question if this post from another thread is accurate:

_ 02-26-2011, 06:27 PM #18 
_
_ *LARRY01Z28*_


_standard radio does not have an amp or any wires in the rear to tap into. you have to tap into the speakers wires at the door locations 
_​


If this is true, how am I seeing some people replace the head unit only? If you're removing the factory unit designed to power speakers @ 2 Ohm impedance and replacing it with an aftermarket HU designed to operate with a 4 Ohm impedance load.... ??? This may shorten the life of a head unit and/or cause it to run hotter. Maybe worth the risk for someone running a lower end head unit, but I don't think some are aware of this risk and may not take it if they were. I know there are a lot of opinions out there on this topic, but most manufacturers do not recommend running 2 Ohm loads off of their units.


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