Understanding E30 speaker and amp wiring

[SPOautos]

Do you happen to know if you have the "premium sound" with tweeters in the doors? This is the easiest indication of whether the car came with the amp or not. Depending on what power output the Kenwood stereo has, it's likely that bypassing the factory amp is your best bet. The process is fairly simple as long as you're comfortable cutting into the stock harness. It is a bit destructive and, depending on how cleanly you do it, can or can't be easily put back to stock at a later time.

At the amp, you just need to identify input wires (one per channel, they share a ground) and tie them to their corresponding output wire (plus add ground wires since stock output uses two wires). The speaker wire in the later models include +ve and -ve and are decent enough for a basic system. If you'd rather replace the amp altogether, that's likely to be even more work as you're not going to find something that uses the factory plug and you'll have to work out how to get signal to it, along with power.

On my build I just added RCA down the center console, out to the trunk, and am leaving the speaker signal disconnected at the head unit. I'm replacing the factory amp in my car with an aftermarket and reusing the existing twisted pair speaker wires for simplicity.

Lastly, if you find that the speakers need replacing (and you have tweeters) keep in mind that the passive crossovers were built in to the 5.25" speakers so you'll want to take that into consideration when purchasing replacements.

Yes, it's the premium sound....well, it has the trunk amp and separate tweeters so I suppose that's premium sound.

Do you know if anyone has ever made jumper wires at the amp to go between the input/outputs? If it the connectors have to be cut off in order to bypass, then I think rather than cutting them, I might buy a 4 channel amp and run RCA's from the head unit. That way I can leave the factory wiring alone. Do you happen to know what gauge power wire and size fuse is powering the factory amp? Could I use the factory power wire for a 4x75rms amp or something like that?

When you were talking about the passive crossovers being built in to the fronts, I don't think I'm following. Are you just saying to make sure I get speakers that come with a crossover?

Thanks for your help!!!

[BSAmarc]

Do you know if anyone has ever made jumper wires at the amp to go between the input/outputs? If it the connectors have to be cut off in order to bypass, then I think rather than cutting them, I might buy a 4 channel amp and run RCA's from the head unit. That way I can leave the factory wiring alone.

I would reach out to bradnic@oemhifi.com to see if he has anything.

Do you happen to know what gauge power wire and size fuse is powering the factory amp? Could I use the factory power wire for a 4x75rms amp or something like that?

30A fuse, 14 gauge wire. Since _all_ wires in and out of the factory amp go through that single that connector, you'd need to hack up the connector to get to them anyways. Better to wire up a new amp using new cabling. Since coupes and sedans have the battery in the trunk, there is an unused channel on the passenger (right) side of the car running all the way to the trunk that you can use for your cabling.

When you were talking about the passive crossovers being built in to the fronts, I don't think I'm following. Are you just saying to make sure I get speakers that come with a crossover?

Correct. Don't just pick up 5.25" speakers expecting there to be a separate crossover behind the panels. Either buy a component sets or a separate crossover.

[SPOautos]

I would reach out to bradnic@oemhifi.com to see if he has anything.


30A fuse, 14 gauge wire. Since _all_ wires in and out of the factory amp go through that single that connector, you'd need to hack up the connector to get to them anyways. Better to wire up a new amp using new cabling. Since coupes and sedans have the battery in the trunk, there is an unused channel on the passenger (right) side of the car running all the way to the trunk that you can use for your cabling.


Correct. Don't just pick up 5.25" speakers expecting there to be a separate crossover behind the panels. Either buy a component sets or a separate crossover.

Thanks for the info! Okay so I can just leave the input connector alone, run a 8 gauge power wire, two sets of rca's, and auxiliary wire, down the passenger side and I guess they snake through the convertible top compartment and into the trunk. I suppose for the speaker wires I'll have to either cut the connector off or depin it.

What do you think is the best way to mount the amp in order to use the factory speaker wires? Just somehow attach it to that back wall where the original amp is? Id like to do it without drilling any holes, but not sure if that'll be possible or not.

[BSAmarc]

I don't know what the trunk space looks like in a convertible, but I'm looking to mount mine to the rear of the back seat, on a board that sits behind the cardboard panel. So the install will be:

steel back seat | wooden board | cardboard panel | amp

This way I can size the board to match existing holes and bolt the amp solidly to it.