On my 90 SSE, does the gain control use a line-level input or a speaker level input from the factory deck? I want to hook the preouts of my cd deck up to the gain so i can use it as a sub control. That way I dont have to run new wires to the trunk.

I don't remember the difference between line level and speaker level, but I put RCA convertors on those lines and fed those into my amp. Seems to work as intended.

Line level is the outputs on the back of a deck that have RCA connectors, these supply a low voltage signal . Speaker level are the amplifier outputs, much higher power

I do belive you have speaker level outs. My Bonneville had the gain control which i got to work with my Sony deck, basically all the gain control amp needs is power, it gets this from the power antenna, basically your gain control will only work with the radio on FM or AM, not at CD. To make it work, attach your power antenna connection to the AMPLIFIER aux.power connection on the back of your deck, your power antenna will always be up when the stereo is on, but its worth it, because the gain gives nice bass sound.

My deck has both amp and antenna power ON. What I am asking is if i can hok up the gain control to the AUX out on ym deck. I only have stereo preouts. I want to use the amp as a hig level input on my sub amp.

Hold on, the stock amp is wired into the stock harness. It should be plug and play for a new head unit with a harness adapter. Just run the stock 6x9 leads to the new sub amp. I used RCA convertors on them, and just made sure which set of leads were bass, and which were midrange.

That would work except that i want to use the rear speaker leads to go to a 4 channel amp and the gain wires for the sub amp. I am going to use the speaker outputs on my deck as highlevel INPUTS on the 4 ch amp. I want to use as much of the stock wiring as i can. And I am asking because, like you just said, the harness can be reconfigured with the wiring.

I see where you're going now...

Curious, does your car have the tweeters in the rear?

WHOOPS maybe I should have mentioned that i have the Performance Speaker option.