Replacing Factory Head Unit w/ Alpine [Archive] - Bimmerfest - BMW Forums

: Replacing Factory Head Unit w/ Alpine

05-28-2007, 08:35 AM
I would like to replace my factory head unit (1998 328i w/ 10 speakers) with an Alpine. I was told that I will need to purchase a Pac OEM-2 in order for the Alpine to work. Does anyone know if this is true? If so, will this unit work with the factory setup or is there something else I should buy?

I'm only asking because I did a search and I see where some people have used it, and other's didn't. So I'm somewhat confused. I plan on adding an aftermarket amp to power a sub only. I'm leaving the factory amp for the existing speakers.

Thanks in advance!

05-28-2007, 09:18 AM
Your OEM BMW HU has front and rear speaker-level outputs.

In EU cars, you could buy the car with a lower-end sound system than you could in the US. In the US, all BMWs at that time and since have had external amplifiers running more than 4 speakers. In EU cars, and cars for other markets (AUS?) you could get a basic deck-power to F and R speaker setup.

Your OEM BMW amplifier is designed to take speaker level inputs.

You can connect the speaker outputs of your new deck to your wires going to the amp, and it will work fine. You will have a crappy amp and crappy speakers which are deteriorating as we speak, but it will work as well as it does now.

Most shops and most people don't understand OEM HU-amp systems or OEM systems in general.

Now, if you put in an OEM-2 - or an SVEN4, or something like that, it will serve as a ground-loop isolator, and sometimes someone has some RPM-related background noise and uses one of these Line Output Converters to get rid of it. In a BMW, you're not doing anything magic to the signal with one of these, you are only eliminating a ground loop, which doesn't seem to happen that often with this sort of replacement. So don't buy one.

And search the forum for what frequently causes audio only with the radio, and none with the CD, after installing a new aftermarket HU into a BMW, and how to fix it :)

05-28-2007, 09:49 AM
Thanks for the input! :thumbup: So would you go through and replace the factory deck, speakers, amp, etc?

I've done this dozens of times in American cars, but never in a setup like this. We can talk off the site if you would like.

05-28-2007, 09:59 AM
Happy to help, but I'd take my email off of public display like that... spam o rama :)

05-28-2007, 10:26 AM
PM sent.