Ok, I've made some progress in replacing the head unit in my '98 328is (HK sound system) with the Empeg MKII but have a question about the connector. I bought an BMW connector adaptor and carefully matched the wiring to the Empeg ISO adaptor. Unfortunately, I get no sound. I did notice another white connector (12-pin) that connected to the original head unit but was that just for the CD changer (I used to have one) or is it an additional connector to the HK amp? Also, will the line level output from the Empeg match the 5v input I believe is required by the Harmon Kardon amp?

Thanks,
David

The empeg ISO adapter only contains wires for power, ignition, remote turn-on, etc. There are no audio cables in that adapter.

In order to get sound out of it, you need to connect the audio cables (the red/black pairs labeled FRONT and REAR) to an amplifier. I don't know about connecting line-level plugs to the factory BMW amplifier, you might need yet another special adapter to do that. I don't know what the BMW amp is like.

The other option is to use an amplifier of your own, skipping the factory amp completely.

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Tony Fabris

I also wired the audio cables from the Empeg cage (using a spare phone plug adaptor) to the BMW connector adaptor, which has leads for FR +/-, FL +/-, RR +/-, and RL +/-. Perhaps the problem is that the line-level plugs are not matched properly to the BMW HK amp? I would eventually like to replace the amp/speakers but for now thought I would start with the head unit. I'm going to hook up my voltmeter tomorrow to make sure it isn't a problem with the Empeg audio output.

Thanks,
David

Are you sure those are line level connections?

Rob

Ah. I see.

There are two possibilities:

1) As Rob just said, those leads to the factory amplifier might be speaker-level connections, and they might need some kind of pre-amplification before you can hear any sound out of them. Depending on the car, you can usually get line-level-to-factory-amp adapters from install shops.

2) It's also possible that the factory amplifier isn't even turning on. It might want some kind of special signal or connection from the factory radio to activate. The factory-amp adapters usually include the necessary connection to make this work.

Either way, a call to a professional install shop (or maybe just a call to Crutchfield) for the necessary BMW-amp-adapter kit should take care of you.

Also, my first comment about using your own amplifier instead of the factory amplifier still counts.

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Tony Fabris

Well, it looks like I forgot to connect the amp power which was why I was getting no sound (LOL). I took care of that problem and now everything works like a champ although the volume is a bit weak probably as you point out because the amp is expecting speaker-level connections. So I guess I should go out and purchase a little line level adaptor which hopefully is not too big since it will be quite crowded back there (don't want to cut any empeg or bmw harness wires). Even with the weak volume, the system definitely sounds MUCH better than the stock head unit even with factory amp and speakers. Anyone know of a good install shop in San Francisco that might have a line-level adapter?

Thanks,
David