Hi all,

I recently purchased a disco 2 v8 from 1999 with only 117.000 km and looking very good.
Off course there are some things that need to be done. One of them is the sound system.
I wanted apple CarPlay and android auto so I purchased a Joying 7" car radio.
Everything is working, steering wheel control, hk amp gets signal to turn on etc.

I can't figure out 2 issues is have with the sound;
1- clicking/ticking/static noise
2- alternator whine

When I turn key to 'acc on' radio turns on and then I get the clicking/ticking/static noise through the speakers as soon as the amp turns on.
Even with the rca cables disconnected from the head unit I get the same clicking/ticking/static noise
With key in 'acc on' position and if I turn on the lights, or open a door, or something else what requires electricity I don't have any sound anymore, it simply cut's out.
Sound comes back when turning lights off, or close the door.
When I turn key to the second position, the sound is also gone and will only come back when I turn the key back to 'acc on' or when I start the engine.
I never experienced something like this before but I don't think it should be this way.

The second issue is alternator whine through the speakers, I know this can be a ground issue so I added a extra ground cable from the headunit to the same ground point the head unit already uses, made no difference.

Previous owner had installed a navigation system that was connect to the original alpine radio, I thought this could be causing the issue so I totally removed the navigation system and cables but it made no difference.

I'm hoping someone has experienced the same and can point me in the right direction, I've been working on this for weeks now and can't find a solution

If the only option is to replace the original HK amp with a new one I'd like to know what amp you advise that works with my 'highline' HK setup.
I already replaced the woofers in the tail door and replaced the 'woofers' and tweeters in the rear doors, front doors and a pillar are still standard.

Cheers!

 

Did you run new speaker wires or are you using the originals? Based on your description I would guess your electrical interference is entering the system through the speaker wiring.

Since that is a guess, my second guess would be did you replace the cable going to the original HK amp under the seat? If so did you use a proper shielded (balanced) cable? That could also be an issue.

 

RCA outputs are unbalanced while the stock amp inputs are balanced. When both get connected, then the amp picks up noise. Check if the unit has balanced outputs and if you can connect them to the DIN/ISO connector of the Discovery. Is an adapter provided with the unit?

 

I battled with the unpleasant noises coming from my Joying unit for a while. Ended up installing a ground loop isolator on each channel, an antenna filter, and some ferrite cable clips. I don't know if all of them were necessary, but they took care of the issues I was having. Sound quality was degraded a bit, but the Rover isn't a listening room by any stretch of the imagination.
The RCA outputs from the head unit are amplified, whereas the outputs in the pin block are not. Passing the amplified signal to the HK amp doesn't make for a good experience.

 

A ground loop isolator makes a balanced signal for the amp out of the unbalanced output of the head unit. This alone should fix any noise issue (if the head unit is properly designed).

 

Original speakers wires still in place, the sound is also present when the amp is not connected to the new head unit, i mean that i removed the rca connectors (metra 70-1786) from the headunit and disconnected the speaker cables from the amp to this adapter.
I did not reaplce the cable going from the headunit to the amp, all is original.

I don't know if the rca outputs from the headunit are balanced, i'll try to find that out. But if that is the issue then the sound i'm getting through the speakers wouldn't be there if the rca is not connected to headunit, or am i missing something?

Can you give me some information on what ground loop isolators you used? And are you sure the rca outputs from this headunit are amplified? I thought only the 'high level' output is amplified on this headunit.

Thanks, headunit is not like pioneer quality or other respected brand i guess.

 

The amp can still pick up noise, if the adapter grounds one side of the balanced inputs. Can you try to leave the brown DIN/ISO connector (amp inputs) open? Then there shouldn't be any noise.

 

I used two of these:
I don't know if I have the same unit as you, but the RCAs on mine are definitely amplified. I had to run the volume setting on the unit at 4 or less or it was too loud. Not sure what you mean about "high level" outputs. The one I have just has the clustered plug and the RCA sockets for audio out.

 

The RCA cables being unbalanced let the interfering noise into the cable and anything it is plugged into. Just because you don't have it plugged into the head unit it is still inducing noise into the amp under the seat where it is plugged in. Unhooked to the head unit it is still like an antenna for the amp which is why you have to apply a ground or ground loop eliminator which is a transformer (inductive coupling.)

Sounds like the best bet would be to use the line level inputs in the multipin connector rather than the RCA's. Second best bet would be adapting the RCA's with the ground loop eliminators, but you still have the high gain amplified signal going to the amp which is looking for line level.

 

I just tried it, brown iso connector disconnected and also disconnected the rca cables from the headunit and still getting the same sound.

There is a volume setting on the radio that you can adjust, I had the same issue.

That probably explains why I get the same noise when the brown iso connector is disconnected and the rca's are disconnected from the headunit.
I'll order 2 rca ground isolators, they're not that expensive. When line level from headunit is connected to the amp, the amp recieves a amplified signal and that is not how it should, right?