hey ya'll, i've got a 94 GT with the mach 460 system in it, with a kenwood head unit. the stereo shop told me i had to bypass the factory amp to add my amp/subs. i'm good with most electrical/stereo stuff, anyone here done it and can tell me how? thanks
There's a bypass harness you can buy, but sevreral of my friends who are certified installers have said you risk blowing the deck in doing so. Weather or not they were right (more than 1 said so), I ripped all the Mach460 crap out and redid my own system just to be absolutely sure I didn't blow my Pioneer 9400. On the flip side though, I have also talked to people that never ever had a problem running an aftermarked HU with the 460 gear.
Edit: Just reread your post and realized you were wanting to add an amp and a sub...That being the case the only surfire way I know of is the way I did it. Out with the old in with the new...Forgive me it's 1 AM...If you only want to do a sub just use your preout on your deck to the amp and wire it the rest of the way up. I can't see the mach460 mids being able to keep up with any decent sub.
If you're just trying to add a sub/amp, just unplug the connector [that's in the trunk, center, top...like you lay down in the trunk and look up] and plug it into speaker-to-line converter, then into your amp, then plug your sub into the amp. Works pretty good for me. You might be able to do a search and find good examples on the forum.
Cruthfield sells a bypass with individual gain controls, I installed it in my car and haven't had any problems since. However I did have my gain turned up to high with my new deck and burnt a driver side speaker, but my fault. If I remember right, it's been a year or so I think it was only $20-$30.