Thinking out loud here....

Has anyone successfully replaced their HK amp with an aftermarket amp and kept the factory wiring? Any "gotchas"? I've seen the wiring diagrams for the audio output, so I think I could figure out how to wire in a 4-channel amp for audio inputs and outputs... Not 100% sure on the remote turn on and power ground wires...

This diagram appears to be the power and control side of the harness:


And this diagram appears to be the audio side of the harness:


ON the audio side, looks like 4 channels from the head unit, and maybe 8 channels out from the amp? In my mind, this could be replaced with a decent 4-channel amp and maybe a couple of cross overs.

 

Following, as I think this is one of the things I'll need to address once I have my R57

 

I did it
if you have an hk system
It's 2 channels in. Front high level from the radio
data in for fading
Out 8 channels out.

Front mid / tweet x2
Front door wooders x2
Rear woofers
Rear tweeters

I tapped the inputs. To a 8 ch dsp. To the front mid and door woofers. Ran new wires for the tweeters. Separate sub amp form dsp
​​​​​​

If you want to run front and rear speakers you need an 8 ch amp. Or at least a set of passive xos for the front to point 300 ish. XO for the back. 3500 ish

I can take pics this weekend I used these diagrams as a starting point but I tested all the pairs myself for polarity etc. not trivial

 

Bumping this as my R57 gets closer to roadworthy
@scott freedman can you provide any additional details on your install? Would definitely be preferable to not have to drop >$1k for a HK replacement.

 

I did pretty much the exact same thing as @scott freedman . My installation uses a Kenwood double din headunit with 6 channels of RCA wires going into a JBL DSP4086 amplifier that powers a Hybrid Audio 3 way component speaker set in the front and the OEM Harmon Kardon 6x9 in the rear for the lower bass notes. The JBL amp is mounted where the OEM Harmon Kardon amplifier was using the OEM metal bracket with a 1/2" wood panel screwed to it.

At the OEM Harmon Kardon amplifier end, I cut off the factory plug and wired in my own connectors using Molex 22pin and 12pin connectors and a larger 2 pin connector for the power wires. I used all of the OEM power wires and speaker wires for my speakers, but had to run new wires for the tweeters up front on the A-pillars.

You can find OEM speaker wire adapters on amazon for the speakers so you don't have to cut off the connectors if you ever want to revert back to OEM. I didn't have to purchase any brackets for the woofers since they were a perfect fit into the hole where the OEM woofer was, but did have to drill new holes to mount it. New brackets for the 3.5" midrange was laser cut at home, which worked out perfectly. The system sounds great and has good volume. The low bass isn't there, but I wanted to save weight so it didn't bother me.

 

I did not change my Headunit.

 

you still are going to drop some money

without speakers. 300 ish for a cheap dsp ( i use a dsr1) then you need 8 channels of amplification or an 8 ch dsp amp
this would do it, all, but i have 0 experience with it.https://www.crutchfield.com/S-M0GZZ6...L-DSP4086.html

I am using the head units front outputs 4 wires. to feed my dsp. then rca to the AMPS than the AMPS feed back into the wire harness for the mids and midbasses in the doors. new wires for the tweeters and sub.

if you keep your speakers they are 2 ohm speakers. this is fine. you need a 4 channel amp for the 2 for front mid tweet left and right 2 for the left and right larger speakers in the bottom of the door. any amp that take high level inputs will work want to cross over the you will want a crossover or bas blocker on the mid tweet channels 250 300 hz
the rear speakers will also need a 4 channel amp if oyu keep them. you need a crossover around 3500 each tweet is its own channel and each mid is its own channel

i can get you colors and photos later.

i ran new wires for the tweeters and run 6 channels from my front speakers. i skipped the rear speakers and a large amp for a sub. i also use a 8 channel dsp with high level inputs.

i

 

Thanks, lower priority for me, for now, after the top & FRM, and some misc trim fixes, but good to know there's a solution that isn't as pricey as the HK