Hi all,

Proud owner of a '99 XJR here. I have the Harman Kardon stereo and recently replaced all speakers (except sub, not wired right now, may do that in the future). Since replacing speakers, there is a high noise coming from the right A pillar tweeter and (to lesser extent) from the right front door midwoofer. The noise level is constant, i.e. not related to volume. There is also a light speaker pop when turning off the stereo. I suspect this is the amp, as it is 22 yrs old and a component may have failed. Visual inspection of the inside of the amp reveals no signs of obvious damages such as bulged capacitors or overheating etc. The amp reads 'LNC4170 AA' and 'A4032'.

If I understand the wiring diagram this amp puts out:

• front L/R: there seem to be separate signals to be coming from the amp (high to A post tweeters and mid to fron doors)
• rear L/R: this seems one signal, split in the door, there is a crude filter on the rear door tweeter

My questions:

1. is my above understanding of split front high/mid signals correct?
2. has anyone succesfully replaced the Harman Kardon LNC4170 AA amp located in the boot for something newer? Also taking into account the split signals for the front speakers. Could something be put together taking a four channel amp and using the right ISO connectors (so I don't need to cut the wiring in the car)? Any specific amp brand/type recommendations?

I know that most obvious thing would be to change to a modern headunit (also having bluetooth etc), but keeping stock appearance is really important to me, so this is not an option. I do not care for a lot of bass, so any amps recommended do not need subwoofer output. Lastly: I have done a lot of research but not found any answers yet, so your thoughts are appreciated!

 

I have not tried installing another amp but, looking at the diagram, it does not seem difficult at all. See the attached extract - I have inserted descriptions for 3 inputs (in red) to the amp, the remaining 4 should be left and right channel inputs. The markings "Ground" and "Amp On" are according to what I found on the net and I cannot guarantee they are correct so you should verify. The "Amp On' line should get +12V when the head unit is switched "on". As for the speakers, it is easy. Just add suitable crossovers (unless you find an amplifier with separate "high", "mid" and "bass" channels.

 

Thank you M. Stojanovic, very much appreciated. I indeed thought about using the crossovers that came with the component speakers.

If anyone has the pinout of IC31 and IC30 that would be great (The diagram is helpful but IC31 contains several similar coloured wires, e.g. 2x slate-pink and 2x slate-orange).

Am I correct that I need 2 Multilock 070 plugs: male 18 pin and male 12 pin?

 

This might be a dumb question but I sincerely don't know...: how do you go get from multilock 070 connector to RCA? Which adapter to use? I take it you use the same ground for all amplifier inputs?

 

Some more photos of the install if you haven't got Instagram.


Bespoke sealed grp rear woofer enclosures and re-modelled ex. mid housings. That OEM plug on the mid was a temporary before the cross overs so I had rear parking alerts.

Alcantara covered beauty panel with rgb cob lighting behind. Nice ;-)!

The wonder that is the DED that allows elimination of the trashy OEM amp.

After bridging channels to the woofers even 14 DSP channels wasn't enough so installed some Focal cross overs in the empty space left by the OEM amp. What the hell it's only fill music!!!