mustang premium sound

First find where the amp is located.  Then look for the wires that are providing the audio signals from the radio.  Here is the deal, the radio probably is sending out preamp voltage since the radio is connected to amplifiers. This means that if you connect a line level converter to your radio the sub will not play because you are not sending the correct signal.  If this is the case what you would have to do is cut the ends off on side of the RCA and tie them into the radio output to the added amplifier.  Everything else should be straight forward. 

just a note:  I'm gonna assume that this is the Mach 460 system and not the Mach 1000 system.

In the 460 system, there are 3 amps--one in the dash underneath the cd player, that powers the tweeters at all speaker locations, and two in the back for the woofers for all locations (one amp for the front woofers, the other amp for the rear woofers).

When I first did a sub amp in one of these I made the mistake of tapping in to the amplifier that's up at the front.  I had used a speaker popper to find the back speaker wires but at the time I did not know that they were bi-amplified and so when I heard the static come from each speaker I just assumed I had found the correct wire.

Needless to say, when I turned on the system to test it all I could hear some faint sound coming out of the sub I had just added, but absolutely no bass came out.  Once I did some research and found out about the rear amps, I tapped into one of those and was good to go.

Do you have a convertible or a hardtop?  If it's a convertible the amps in the rear are mounted to the rear wheel hump.  If it's a hardtop then the amps are mounted to the roof of the trunk, or the underside of the rear deck or whatever you want to call it.  You should check out this page for more info on how to remove trim panels and stuff to get access to the different components.

As long as you get your signal connections from one of those rear amps, a standard Line Output converter is all that you should need.  Also sometime the mach systems use a low voltage trigger for the factory amps, and so to send a proper +12v turn on signal to your aftermarket subwoofer amp, you may need a low voltage trigger such as the LVT from Peripheral.  Not all of them are like this though, and the only way to know for sure is to do it the old fashioned way: grab a multimeter and measure the voltage.  Anything under, say, 10 volts, will probably mean the factory setup uses the low voltage trigger and thus you'd need that adapter from peripheral.  Anything from 10 volts -13 volts should be okay with your aftermarket amp, but if you'r in doubt just try it and see if the amp powers up.

esmith69, I know that you are knowledgeable about car stereos and systems, but I have a question and it's to improve my knowledge and maybe help others out. You recommend placing a LOC

after the subwoofer amp, I noticed that the amplifiers are rated to send out 45 watts RMS. Would this pose a problem to the LOC and possibly fry them in the future from voltage overload.

Here is a link that I found that has some add on items for the mustang system that should help out also.  I am just another car stereo nut that loves to hear it loud and clear. https://www.mustangaudiosystems.com/MustangAudio_page2.htm

Yep Viper's right, you'll most likely use it on the output side of the amp.  Also, almost all LOC's are adjustable which means you can turn down the level if it ends up being too high/sensitive.  However, if the converter itself is not designed to handle the amount of power you send into it, it will have a distorted output no matter how low you adjust its output.

I'd think about getting one from David Navone or Soundgate--both companies make some really solid LOC's and have models that can easily handle the power output of the Ford factory amplifiers.