P38 head unit replacement

Hi all
I have just purchased a 1995 P38 DSE this is our first Range Rover.
I wanted to replace the original (Land Rover) head unit today with a pioneer mp3 head unit i have.
When i took the original head unit out i was very confused when i found 2 antenna cables plugged into the back, and also the power connecter fits the pioneer unit but the speaker connector is too big...
Forgive me for sounding like a numpty :doh: but as i say this is my first Range Rover (loving it so far) any advise on this issue would be much appreciated

BTW just realised i didn't introduce myself
My name is Dan i am 28 and live in south west France

hi the 2 antenna cables dont matter you can use any one of them the speaker plug you are on about is made for the hk sound system as it powers up the sub as well, the good bit is you can by an adaptor lead of ebay for £50 and it is plug and play, I brought one my self and it works well, and other people on here have brought the same with no complaints other than the £50 price of it, the other option is to re wire the whole sound system your self and that way you will bypass the hk amps and have it all running of the stereo. hope that helps you. and good luck with the range rover dare say we will be hearing from you:

Would you mind me asking if the adaptor allows you to still use the steering wheel controls ?

no it doesnt but other people have said you can buy adaptor to do that but ive never bothered with it

Thanks alot for the info I didn't realise it even had an amp and sub...50 quid is a bit steep for an adapter ...but don't fancy attempting to re-wire myself so I might just have to shell out for one then.

I dare say I'll be back for more help with other things in the future, must say though I am well pleased with the car, think I've turned into a 4x4 and off road fanatic

Thanks again for your help!

if you look in the left hand side of the boot there should be a panel there and behind that is the sub box and a little amp all standard with the hk sound system

Standby on the adapter cables - depending on which one - some people have all sorts of issues with some of them. An adapter cable that uses your new head unit's RCA outputs may NOT work, as the required input impedance for the HK door amps is wrong from both standard HU speaker outputs AND RCAs!!!

I'm working on something at the moment, based on Ray Ambler's attenuator circuit - link here - Aftermarket Head Unit Adaptation for Range Rover 4.0/4.6

I've done alot of research on this - from what I've found, the Nexxia adapter leads just won't cut it (the explanation is long-winded, but makes sense)

Clarky130 said:

Standby on the adapter cables - depending on which one - some people have all sorts of issues with some of them. An adapter cable that uses your new head unit's RCA outputs may NOT work, as the required input impedance for the HK door amps is wrong from both standard HU speaker outputs AND RCAs!!!

I'm working on something at the moment, based on Ray Ambler's attenuator circuit - link here - Aftermarket Head Unit Adaptation for Range Rover 4.0/4.6

I've done alot of research on this - from what I've found, the Nexxia adapter leads just won't cut it (the explanation is long-winded, but makes sense)

Click to expand...

Are you saying the unit in this link does not work? Range rover amplifier adaptor lead cable | eBay

No, this loom works well. The quality is as high as the race looms for m Ducatis. Very impressive.

JerryXt said:

No, this loom works well. The quality is as high as the race looms for m Ducatis. Very impressive.

Click to expand...

Hmm, very little useful information in the ad along with spelling mistakes and the claim that the Clarion costs an arm and a leg to fix if it goes wrong.

You can get the Clarion fully reconditioned for only slightly more than the cost of this cable. If anything costs an arm and a leg it's this cable.

I'd be concerned by the way it mentions an external amplifier. My understanding was that the Clarion/HK system consists of multiple external amplifiers.

Does this cable really work? Think I'm just going to get my Clarion reconditioned.

yes, it really does work. I just put a new Alpine head unit in my HK equipped P38 and it works perfectly with the lead. Many people here have used the lead with few or no problems.

You're right that the HK system uses a central amp with individual amps for the door speakers, but the signal from the head unit is taken through the central amp. This loom plugs into the standard loom HK and provides ISO(?) connectors to plug into the new head unit.

If your only concern is the head unit, it may be better to get yours fixed. If you want things like bluetooth and iPod connectivity, its more cost-effective to get a new head unit and this lead.

JerryXt said:

yes, it really does work. I just put a new Alpine head unit in my HK equipped P38 and it works perfectly with the lead. Many people here have used the lead with few or no problems.

You're right that the HK system uses a central amp with individual amps for the door speakers, but the signal from the head unit is taken through the central amp. This loom plugs into the standard loom HK and provides ISO(?) connectors to plug into the new head unit.

If your only concern is the head unit, it may be better to get yours fixed. If you want things like bluetooth and iPod connectivity, its more cost-effective to get a new head unit and this lead.

Click to expand...

Ok, forgive my scepticism, sounds like it was uncalled for.

Clarion will add ipod connectivity at the same time as reconning it, although I accept that bluetooth is probably beyond them.

Mention has been made of the steering wheel controls and the fact that yet another adaptor lead is required for these. Anyone have details of this additional adaptor?

Yes, I got an adapter for the steering wheel controls, but it didn't work. It may be that the adapter was not the right one for my car - the year on the box didn't match my model year. The installer said that the manufacturers are usually very good. He was surprised that it didn't work.

TBH, there are so many more features on the new head unit that obviously aren't on the wheel that I'm not bothered about lack of wheel controls.

I'll do a proper update on my head unit thread later.

The lead you mentioned may not be the troublesome Nexxia one, or they may have redesigned it - not sure. It will work ONLY if it has some kind of attenuation built into it. The HK door amps need a 70 ohm balanced input. Output from a STD HU on the speaker connections is around 4-8 ohms. Output from the RCA pre-outs is in the order of 1Kohm, and is unbalanced. Neither will work if simply connected directly, you will either over-drive the door amps, or under-drive them and introduce ground looping and other interference.

And the HK system (up to 99MY, I think) does not have a 'central' amp at all. The systems that had the Alpine HU fitted as standard (99 on, I think) DO have 1 'central' amp and are a different setup - more success seems to be had with these than the earlier systems.

Ok - update.

New head unit fitted and working a charm. Used the 'Ray Ambler' attenuator circuits on each channel, except the sub which I'm running straight off one of the RCAs, utilising a butchered RCA plug and the existing wiring.

And... WHAT a difference! I will now take back EVERYTHING bad I said about the HK stuff, with a decent input, at the right impedance level, it is MINDBLOWING for a 15 yr old standard system!! WELL worth holding onto if you have the patience to solder up 4 of those attenuator circuits. Great quality sound reproduction at any volume, with virtually NO distortion. Just goes to show you how s**te the Clarion head unit is!

And there's something else... I noticed that, with the original setup, the bass was particularly weedy. When I got the new head unit in and running, even before I'd connected up the sub, there was a HUGE improvement in the bass, even from just the door speakers. After some investigation, it turns out that the factory sub with the unmolested factory wiring was hooked up THE WRONG WAY ROUND!!! When I connected up the sub and reversed the polarity, the difference was unbelievable.

As a 'factory' system, with a DECENT head unit now fitted, it's a rival for any other out there. Seriously, I could not have been more wrong about the HK stuff - a crap head unit, combined with a 180 deg out-of-phase sub made the system sound awful, hence why I planned to replace EVERYTHING. I'm still gonna replace the sub and amp with one of my own choosing though - the HK one is strong, and ballsy, but it has no real 'guts' - I like my bass to shake the windows!

As a result, I will shortly be selling the original head unit, CD changer and sub, if anyone has any use for them. The HU works, the display is a little iffy but still readable. CD changer and sub work fine.

Great job and glad you are pleased with it.

Is there a minimum spec on the head unit replacement which makes this difference or is just a case of a quality unit whatever that may be?

Not that I'm aware of, any quality head unit should do the trick. Make sure it has a MOSFET amp, as this outputs a balanced signal, which is what the door / sub amps expect. Almost all quality HUs have MOSFET amps these days - just avoid the 'cheap and nasty' and you should be ok.

Also worth checking the HUs internal amp distortion levels as you will be using it's output. A distortion of less than 0.1% THD should be ok. Like I said, most half-decent HUs will meet this spec.

JohnP38 said:

Are you saying the unit in this link does not work? Range rover amplifier adaptor lead cable | eBay

Click to expand...

Why the hell is that £42 ...ridiculous!

Clarky,

U willing to knock me up one?? Obviously, I will return the favour with tokens....

I bought the nexxia one!! What a load of ****. The eBay lead only work on older systems, I got a 2002 model.

We be a good temp fix until the whole system goes in when it's warmer!!

James.