P38A stereo replacement

Good afternoon guys and girls, I have a dilemma to which I need help and advice, its probably been asked many times before and I have gone through previous posts and not really found the answer. I did have the a similar problem before on my 50th anniversary, but this was fixed by another member on here with a bit of wiring magic he had made. So my question is as follows Range Rover P38A 2000 4.6 HSE, I have replaced the standard stereo with a single din Pioneer head unit, the car does have the harmen carmen amplified system fitted, I did purchase a new wiring loom to connect the head unit to the harmen carmen system, But when I had finished fitting it all there is hardly any volume, what have I done wrong and what do I need to correct it, thanks in advance
Andy

Hey buddy, I swapped my original unit for a more modern one, but I didn't need any extra wiring for mine?
Only the three little plugs weren't used.
Have checked the adaptor kit to make sure it's all seated together properly?
Don't forget also these buses have power amps in them, so your old unit acts as a pre amp. Unless you could have damaged power amps?
Was it all working at the correct volume levels before?

Got a vague memory the Harmon Kardon system has different resistance to most systems or something. If you change the head unit you may have replace the whole thing. Then there's that DSP thing in the boot. From what I hear it is a right PITA. @martyuk knows more about these things although I am sure there are others on here that do.

I've the Harmon system in mine, I now find that the new stereo works at much lower volume and stays that way as not to over power the power amps in the bus!
The original stereo gives only a low signal volume range and the separate amps amplify it upwards.

It all depends how you connect the Pioneer to the HK system. Options are:

1. There's an adapter box that basically takes the speaker outputs from the after-market stereo, and feed the the HK balanced inputs via some resistor ladders, but this often results in buzz or hum loops.
2. Connect the RCA Line outputs using RCA to 10-pin HK connector. In this case one side of the balanced inputs connects to the Pioneer ground. Volume is often low because the HK expects higher level input than the Pioneer RCA provides.
3. Proper DIY solution: Use 5 x Balancing transformers between the RCA Line outputs and the HK inputs. This is the best method because it retains the audio balancing which avoids hum loops, plus the balanced audio removes any vehicle interference on the line outputs.

I used five of these from RS Components for my system, and the result is excellent. Same solution works for any after-market stereo with RCA / Phono Line outputs, and the HK door amp system.

Mark Piercy said:

Hey buddy, I swapped my original unit for a more modern one, but I didn't need any extra wiring for mine?
Only the three little plugs weren't used.
Have checked the adaptor kit to make sure it's all seated together properly?
Don't forget also these buses have power amps in them, so your old unit acts as a pre amp. Unless you could have damaged power amps?
Was it all working at the correct volume levels before?

Click to expand...

Hi Bud
Thank you for your reply yes the system was working good prior to removing the old Alpine head unit

If you have the DSP amp in the rear you can't just go swooping out the head unit

pwood999 said:

It all depends how you connect the Pioneer to the HK system. Options are:

1. There's an adapter box that basically takes the speaker outputs from the after-market stereo, and feed the the HK balanced inputs via some resistor ladders, but this often results in buzz or hum loops.
2. Connect the RCA Line outputs using RCA to 10-pin HK connector. In this case one side of the balanced inputs connects to the Pioneer ground. Volume is often low because the HK expects higher level input than the Pioneer RCA provides.
3. Proper DIY solution: Use 5 x Balancing transformers between the RCA Line outputs and the HK inputs. This is the best method because it retains the audio balancing which avoids hum loops, plus the balanced audio removes any vehicle interference on the line outputs.

I used five of these from RS Components for my system, and the result is excellent. Same solution works for any after-market stereo with RCA / Phono Line outputs, and the HK door amp system.

Click to expand...

Hi thank you for the info I just wished I understood it lol

biketeacherdave said:

If you have the DSP amp in the rear you can't just go swooping out the head unit

Click to expand...

I totally understand that now, why are things made so complicated lol