A few months ago my H/K amp fried. As we all know, the replacement amp is $900+ , so I wasn't about to go this route. Instead, I purchased an aftermarket setup.
In this post I hope to share the process and the problems/solutions that I've encountered during this install to aid a "Do-It-Yourselfer" in the process.
Note: I assume you have basic knowledge of taking the car apart, and of installing basic car audio equipment. If you have any questions, I will be happy to help.

Here's what I got:
A) Alpine PDX-5 -- 5 channel amp so i could run a sub in the future, you could use the PDX-4 or any other 4 channel amp) $350 Shipped New from eBay. This is a miniature sized amp so that it will be easier to install in the car.
B) Kenwood X993 head unit -- I choose this one b/c it blends in a more like a stock unit, and you can change the colors on it to match your car. I also like it for its bluetooth and ipod/iphone support. For those who don't know, you can't use the stock head-unit with another amp b/c it sends the sound data through a proprietary digital signal to the h/k amp. $245 Shipped New from Amazon
C) Stock Speakers (for now) -- I decided to keep the stock speakers for now since they already sound pretty good, and because I ran out of money.
D) Stock Speaker wiring -- I also decided to keep the stock speaker wiring because rewiring the front two doors is nearly impossible because the wires that connect the chassis to the door (the black rubber tube you see when the door is open) connects with a plastic plug that takes up almost all of the space (NOTE: the wiring color scheme in the door speakers change to different colors after they go through the above plug............grrrrr). I suppose you could drill into the chassis, but i didn't want to go this route.
E) Antenna adaptor off Amazon $7.69
F) Generic BMW wiring harness off Amazon $7.69
G) Faceplate adaptor off Amazon $11.69

Total Cost: $622.07


Installation:
1)Take the car apart: I'm not going to go into detail with this, just follow the Bentley manual or some tutorials on NAM.
2)Run 2-3 RCA cables from your head-unit to the boot where your amp will be located.
3)You will need to also run two more wires, one for the remote on for the amp, and the other for the diversity amp (see below). I suppose you could use the existing two twisted "Data" pairs for this job, but i just decided to run a new two line wire.


4)Cut off the plug on the wiring bundle that the original h/k amp used. Below is the wiring diagram that i discovered through trial and error.



For the front mids and tweeters, I hooked up each channel in parallel. This front speaker setup is still in debate by me and my electrical engineering g/f. See the problem exists that i don't know the impedance of the tweeters so i cant calculate the total impedance load on the amp. I will post more on this when i get a chance. For the rear 6x9's, I hooked each channel in series, since they are dual voice coils, this ensures they run at 4 Ohms. For those of you that didn't understand that, for the left front i twisted the tweeters plus and the mids plus together and hooked that up the amp, and did the same for the minus. Then for the rear 6x9's, I hooked the plus from the top connector of the speaker to the amp, then the minus from the top i hooked up to the plus on the bottom, then hooked the minus on the bottom to the minus of that channel on the amp. Also, in this step I had to extend each wire about a foot so it would reach my amp.





5)Solder your head-unit wiring harness to the wiring harness you got off amazon. In this step you only need to solder the Power, Ignition, Ground, Illumination, and Power Antenna connections (you will also need to solder one of those wires you ran earlier that connects to the diversity amp(white wire, see A above) to the power antenna wire coming off your head-unit). You can skip all the speaker channels as you won't use them.
Use the following diagram to get the correct wiring.




Note: There are three, yes I said three antenna amps in our mini according to the Bently manual. Two of them are, I assume, powered by the antenna wire in the BMW wiring harness adaptor at the head-unit. The third is not; it is diagramed in the Bentley manual that all three of these amps connect via a common wire, and since the diversity amp is remotely run by a wire that goes to the stock h/k wiring plug we just cut off, you need to use that extra wire that I suggested running. Solder one end in the boot to the white wire in the old H/K plug, and the other end to where your headunit has an antenna pwr out where it connects to your BMW's audio wiring harness you got.


6)Solder your remote on from your head-unit to one of the wires I told you to run earlier. Connect the other end to your amp's "remote on". Plug in your RCA cables to the amp and the head-unit.

7)Install your head-unit, and mount your amp. Next Run Power from your battery to your amp and make sure you use a fuse in line.

8)You're done!







I had a custom bracket built out of aluminum to hold my amp, I did this in my dad's metal shop, so i don't know the cost it would be if done by someone else. I'm sorry if this tutorial is vague or incomplete. I've never written a tutorial before, so give me some feedback. Please Sticky if you find useful. Good Luck!

 

Nice write up, looks good.

As for the fronts i think it would be best to wire up a crossover in the door.

Applying a full range signal to speakers that can produce full range will just muddy things up and decrease over all sensitivity. (im not an expert thought)

somewhere on nam is the approx crossover points and resistance.

Ill have to keep this in mind if my H/k goes again?

-Jonathan

 

Ya I thought about using a crossover, but I didn't have one at the time of the install. The setup right now bothers me since its its hooked up like this. As for the tweeters, they have an inline filter which takes out the lows, and the mids in the front cant really produce any highs. Anyways I still think I am going to invest in a pair of crossovers.

Thanks for the feedback!

 

In your picture between steps 3 and 4. I do not have that in my car, a 2005 MCS w/ HK system. Maybe that would help with my reception, which has always been kinda crappy, which is what I'm looking for here right now...

 

Have you looked on the driver side? RealOEM shows it as being on the driver side rather then mine which is on the passenger side.
http://www.realoem.com/bmw/showparts...08&hg=65&fg=30

 

Yup, not there either. I've had both sides off lots of times doing sound dampening and trying out different 6x9's, but never seen this thing. Again, maybe that's why my reception is SOOO crappy...

 

Here are some very informative, albeit additional to what you have already posted here.

Main site.

Direct links to HK wiring info

Black Plug.
Gray plug.

 

I took my center section apart today to install some gages under the switches, and I got to thinking about installing a new HU while I had it apart. I took off both back interior panels just to verify that I do not have this diversity amp.

Question is, would it be worthwhile buying it, and the cables to/from it/back window to help with my reception?

Anyone ever heard of adding this on to their car?

 

Isn't the diversity amp only for cars with the factory nav and/or phone options? I don't think it boosts radio reception, but not sure...

 

That could explain why I don't have it. Looking at Realoem.com, for the HK system it doesn't appear to be part of it. But, the OP who started the thread must have the HK system, and had it...

 

it is interesting!

 

Is it possible to just bypass the amp so I can run a Kenwood head unit without the amp problem I encountered?

 

Not necessarily true based on other threads here. One for example:
https://www.northamericanmotoring.co...-mrp-f300.html
But great writeup!

 

You shouldn't be sorry! This was a very detailed how-to with tons of info.

Thank You!