The Duchess has decided to start making a banging noise. Not a mechanical one, but when she's parked the speakers thump loudly, even with the key out. This is has got so bad I can hear it in the house and it has flattened the battery!
What is the remedy? In the meantime, knowing which fuse(s) to pull would be really helpful!!
While we're at it... does this look like a good idea? I don't ever use the DSP presets anyway: https://carphonics.co.uk/shop/shop-by-car/range-rover/range-rover-p38-1994-2002/land-range-rover-p38-harman-kardon-amplifier-replacement-xqk100340/
I assume the Duchess has the DSP amp? If it has, there are two fuses that supply permanent live to it, fuse 1, which also supplies the head unit, the clock, instrument cluster, window switchpack amongst others and pulling that one causes the radio to lose any stored settings and the trip computer to resent to zero, and fuse 15 which also supplies some of the interior lights and the tailgate latch. So probably better to pull fuse 15 initially.
She does.
Arse. I think I'm going to disconnect the battery, and physically pull the DSP.
If the fault leaves with the DSP then I'll be looking for alternatives.
Thanks! as ever...
Well that was a lot of digging to get to the amp! Anyway, it's disconnected now, and the ticking/thumping has stopped.
So that's good.
I guess it's time to pay up for the replacement, a mere £250 if you please. But, it's better than rewiring the whole car IMO. I realise that Marty and others have come up with replacement door amps etc, but I'm going to go with the pay, plug and play option due to <s>:laziness</s>: err wanting to keep it as original as possible.
OK, laziness.
Hmmm front speakers only. I shall make enquiries.
Did you get the exact replacement? A DSP amp from a Disco has a very similar part number and will work in a P38 but with front speakers only.
That's the thing. The page promises everything will work apart from the DSP "concert hall" type features. If it's just a Disco amp then I'm unimpressed as they claimed that they modify an amp to work fully with a P38.
I have emailed them.
The P38 system only supplies left and right channels to the amp and signal is split inside the amp to feed the rear speakers. When installing Marty's alternative, you have to run additional wires from the rear outputs on the head unit (which are there just not used) to feed the amps that drive the rear speakers. Without a full circuit diagram I don't know if you would be able to run the additional wires to the Disco amp and make the rears work.
If you don't have the DSP features, it sounds almost as if they have done a similar job to Marty (who used 4 door amps from earlier pre-DSP cars) or something similar to what I have all the bits to put together but just haven't got around to it (see https://rangerovers.pub/topic/8-info-p38-alpine-dsp-amp-connections-and-wiring?page=1#pid30814) rather than supplying a DSP amp.
And much WhatsApping later, the amp is going back to be inspected. It should drive the rears and subs but it doesn't. My old amp, however, is doing just fine after some.. <cough>contactcleaner<cough> was used to do some serious maintenance. Ah well.
I'm still interested to know if there is a DSP alternative available to us as I'm sure I'll need one sooner or later.
Gilbertd wrote:
The P38 system only supplies left and right channels to the amp and signal is split inside the amp to feed the rear speakers. When installing Marty's alternative, you have to run additional wires from the rear outputs on the head unit (which are there just not used) to feed the amps that drive the rear speakers. Without a full circuit diagram I don't know if you would be able to run the additional wires to the Disco amp and make the rears work.
If you don't have the DSP features, it sounds almost as if they have done a similar job to Marty (who used 4 door amps from earlier pre-DSP cars) or something similar to what I have all the bits to put together but just haven't got around to it (see https://rangerovers.pub/topic/8-info-p38-alpine-dsp-amp-connections-and-wiring?page=1#pid30814) rather than supplying a DSP amp.
Yes, that's all true - but it remains to be seen if this is a disco amp or not. The claim is that it's another HK amp that has been modified to work with the P38. If that is the case, it could still be a disco amp I guess, but if it's possible to modify one to work with the P38 without the door amp shenanigens I'm all for it!
Just had a thought, I've got the Disco 2 diagrams so checked them. The version with the HK DSP amp does indeed have all four (left and right, front and rear) outputs from the head unit going to the amp. The rear inputs from the head unit go to pins 8 and 16 for the rear right channel and pins 29 and 37 for the rear left channel. If you look at the diagram in the thread I linked to, you'll see that these pins aren't used in the P38. So, in theory, two extra pairs of wires from the head unit to the amp and connected to those unused pins in the plug and it should work. In theory......
But if that is all that is needed, anyone with a dead DSP amp could buy the considerably cheaper and more readily available Disco amp and just fit that and add 4 bits of wire.
Just had a thought, I've got the Disco 2 diagrams so checked them. The version with the HK DSP amp does indeed have all four (left and right, front and rear) outputs from the head unit going to the amp. The rear inputs from the head unit go to pins 8 and 16 for the rear right channel and pins 29 and 37 for the rear left channel. If you look at the diagram in the thread I linked to, you'll see that these pins aren't used in the P38. So, in theory, two extra pairs of wires from the head unit to the amp and connected to those unused pins in the plug and it should work. In theory......
But if that is all that is needed, anyone with a dead DSP amp could buy the considerably cheaper and more readily available Disco amp and just fit that and add 4 bits of wire.
Great info!
I wonder if our chap is moving the connections around in a disco2 amp to match the P38 pinout?
From what I can see, there are no connections to move, all it needs is the 4 additional wires adding.
Oh OK. Well I certainly haven't added any wiring, this was meant to be plug and play. Curiouser and Curiouser.
Does it still have the part number on it or has that been taken off?