RangeRovers.net Forum banner

1 - 15 of 15 Posts

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #1
I've seen a few posts on this subject before but all the ones I've seen said that only certain (mostly front) speakers will work. Having finally completely blown up my DSP, I bought an E46 amp and have managed to get all 12 speakers working properly. It's not too hard but does involve running additional wires from the head unit to the amp.

The big attraction is cost: approx £30 for the E46 Amp as opposed to ten times that for a DSP amp. Obviously I've lost the DSP effects and also the BMW unit doesn't have the Navigation input or surprisingly a phone mute (neither of which I use). Adding an Aux In is also a little more difficult / expensive but can be done.

If there is any interest I can explain further.
 

·
Premium Member
2002-2005 Range Rover MkIII / L322
Joined
·
3,622 Posts
Please do a write up. I'm just about to either do what you did or replace my DSP amp with an amp I've had melting in my attic for the last 10 years.

Do the subs still work with your BMW amp?
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #4
I’ll divide this into two parts: first I’ll try to explain what the differences are and what you need to do to make it work, second I’ll give details of what I actually did. I’ll try to keep it short(ish) so ask specific questions if you want more details.

Starting Point
My P38 is a 2001 Vogue with the Premium System – Alpine head unit, XQK100340 amp, 3 speakers in the front doors, 2 speakers in the rear doors and 2 speakers in the sub. My sat nav died a long time ago so this was not a consideration for me.

Replacement Amp
Both the E46 and Disco II amps are physically similar and the connectors physically fit. A bit of research showed that they all had roughly similar speaker set-ups and the wiring wasn’t that different, so modifying rather than starting again looked possible. I choose a BMW amp as they are generally cheaper than Disco ones and fairly plentiful on eBay. Mine’s part number is 68 12 8 388 068. You can look up BMW part numbers on www.realoem.com as BMW seem to change the part numbers often. Mine was from a coupe. Saloon part numbers are different but I don’t know if the amps are actually different.

The following pictures show the differences in the circuit boards (DSP at the top – two orange wires are mine – part of a subwoofer experiment). Although they appear very different at first glance, the power output drivers (the four vertical chips at the bottom) are the same part (TDA8563Q) are the same. Both amps therefore have 8 x 40W outputs so if we can connect these to the appropriate speaker(s) we should be in business. On the RR the outputs are: 4 base units in each door + 2 mid & tweeter in the front doors + 2 mid in the rear doors. (I’ll cover the sub later).

IMG_20170524_120414418.jpg

Head Unit / Amp Interface
The Alpine head unit has 5 balanced outputs (2 front, 2 rear + sub)
The DSP only uses the two front inputs and generates the rear outputs (and the sub output) internally, whereas the BMW amp needs four inputs (2 front + 2 rear). So if we connect the rear outputs from the head unit to the amp we should get all 8 channels.

Subwoofer
The DSP does not use the head unit sub output but generates it via one of the DSPs. It feeds the signal through a low pass filter before outputting an unbalanced output to the DSP amp (this lives in the sub box). The BMW amp doesn’t have a sub input or output (maybe this is the difference between the coupe and saloon versions?), so we need to connect the head output direct to the sub amp. Slight problem is that the head provides a balanced output whereas the sub is expecting an unbalanced input. (Google will probably explain this better than I can if you don’t understand). Maybe you could connect both but it is safer to only use on wire, which is what I did.

Wiring
Rave will give pin numbers but you need to know what the wires do so look at Marty’s post in the Alpine / DSP wiring sticky. For an equivalent BMW listing try the 8[SUP]th[/SUP] post in this thread.

http://forum.e46fanatics.com/showthread.php?p=15289065

The BMW amp has connections for two extra mid-range speakers but a quick probe with the multi-meter shows that they are just duplicate connections to two of the power amps that allow two speakers to be connected in parallel. On the RR we can use either pair of outputs but we need to be careful that there is nothing connected to the second pair.

Now it’s simply a question of getting all the wires in the right places!
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #5
Part 2 – What Goes Where!

Warning, there are two reasons you should not follow this guide blindly:
1) Your car or amp may be different to mine,
2) I may have made a mistake in transcribing these instructions. Look at the diagrams. Check the wire colours and ideally use a multi-meter to check where the pins / wires go.

Head Unit
We need to use all 5 outputs from the head unit. The two front outputs are obviously already connected on the standard ISO brown connector and so are the sub outputs – orange & orange/black wires on the yellow part of the mini ISO. We therefore need to run two twisted pairs from the head unit to the amp. These go from pins 1,2 and 7,8 on the brown ISO connector to pins 8,16 & 29,37 on C0491 (the amp connector). As they are balanced outputs it doesn’t actually matter which way round the two wires in the pair go but you need to get the left / right pairs correct for the balance control to work the right way round. The wires need to be about 5m long. To make a twisted pair, take two wires – put one pair of ends in a vice and the other in the chuck of a drill then rotate the drill. The spiral will spring back a bit but the twists don’t need to be very tight anyway. The pins for the ISO connector are widely available but C0491 is a bit more of a challenge. I used these:

http://uk.farnell.com/te-connectivity-amp/963729-1/receptacle-crimp-snap-in/dp/1330227

C0491
This is actually two connectors which are easily removed from the outer shell. The pins are also very easy to remove (joy!) use a small screwdriver to press the tab and then pull the wire.
The front and rear right base units are reversed between on the BMW so we need to swap the wires over: 22 swaps to 24, 23 to 25, 24 to 22 & 25 to 23.
The RR has the telephone input on 41,42 but these are one of the duplicate speaker outputs on the BMW amp, so I would remove these.

Subwoofer
The BMW amp does not have a sub input or output so I would remove both the input and output wires from C0491 – orange, orange/black pairs on pins 6,14 & 39,40. 39,40 is the other duplicate speaker output so you could leave the sub amp input on these but you wouldn’t be able to control the relative volume and I don’t know whether the power output stage would like having a speaker and the sub amp in parallel.
Much better to wire the sub output from the head unit direct to the sub amp. It is safest to only connect one wire (connect either the two oranges OR the two orange/blacks). Google “connect balanced output into unbalanced input if you don’t understand why.

Minor issue is that the mounting bracket is different - just use the end cap from the DSP amp in place of the BMW one.

That’s it. If you’ve got it right the balance, fade, & sub controls on the head unit should all work as you would expect.
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,218 Posts
The subwoofer should still work, if you're using the P38 head unit, as they are driven independently to the door speakers on the P38.

I'm not saying the Disco 2 Amp (XQK100210 from memory is the common one) won't work - I did look into trying one of these a few years ago, (before looking into making my 'DSP replacement' boards, using standard P38 door amps), and I'm sure there was a reason I didn't pursue it..

I looked into it a bit again this evening, as something was niggling me about the pinouts on the D2 vehicles. (again, not saying it doesn't work - as it would be a far cheaper option!)

Whilst you would have to run the extra wiring for the rear left/right feeds - which you'd have to do on any replacement option, which doesn't involve the painful expense of the replacement XQK10340! - the D2 outputs are also slightly different to the P38 outputs.

The P38 was wired with each door getting a separate feed to the woofer speaker, and a feed to the mid/high speaker (which splits to the tweeter in the front doors).
The D2 wiring shows that the front doors are pretty much the same as the P38 - 2 separate feeds, one for woofer, one for mid/high, which splits to tweeter aswell.
The rear doors of the D2 however appear to get a full range feed, and in the rear doors the woofer and mid/high speakers are joined off of one feed each (where the P38 ones are separate), and then the other 2 outputs on the D2 amp are then fed to the woofers which were fitted in the tailgate.

I'm just wondering if there's any effect on how the audio is handled by the D2 DSP amp, with the rear door feeds giving a full range signal (which I presume when connected to the P38 would feed the mid/high speakers) and the other outputs (which again I presume would then feed the woofers in the rear doors) effectively being the 'subwoofer' in the D2, where the P38 has the separate subwoofer feed and the standalone subwoofer unit with it's own amp.

Does it make any difference to the audio with the mid/highs in the rear doors being fed full range signal, rather than filtered signal, as with the P38 amp? And does the balance/fade work OK? (I've never heard the D2 setup, so don't know if the DSP amp for that is programmed to fade the 2 subs in the tailgate, or whether the firmware has them being controlled as what would be the separate 'subwoofer' control)

Were there any pins that had to be swapped around on the D2 amp aswell, or other than adding the rear left/right input wires, did they all match up to P38 wiring (I remember looking at this a couple of years ago too - but didn't make any notes about it that I can find!)

Marty

EDIT: - It looks like we were typing at the same time! I have a feeling the subwoofer amp on the P38 is supposed to be a balanced input aswell, I don't know how the DSP amp fiddles it, as I've never got around to playing with it that much.. But I had an unbalanced line level input to my subwoofer amp, and it sounded horrible - a lot of noise on it and popped with head unit turned on/off. I've recently just made myself an unbalanced to balanced converter and wired that in, and it has cleaned the subwoofer signal up a lot, and it has much more punch than it did when fed the unbalanced signal - and the power up/down pop has gone too!

It also looks like a lot of what I've posted is irrelevant, given you've used a BMW amp, rather than Disco 2 - if that works, then maybe the way to go, as I say, I don't know if the internals of the D2 DSP amp are configured differently because they've utilised the output differently again to the BMW version.

Good to know there are other workable options out there though!

EDIT 2:
Just looked in the D2 RAVE ETM, and the wiring for the speakers on that is even more different.
It appears the 'high line' system in the D2 is effectively a 5 channel amp (rather than the 8 channel + sub out of the P38 '340 amp) with a mid/high range output to each door, and the the 5th amplified output is ALL the low range speakers together - both front doors, and the 2 in the tailgate door. So definitely looks like the BMW option is better than the D2 amp!
 

·
Premium Member
2002-2005 Range Rover MkIII / L322
Joined
·
3,622 Posts
So a short Cliffs notes version... If I use the BMW amp and just do a direct swap plug and play I'll end up with working fronts, no rears, and no subs... correct? I'm actually ok with that because I want to run a dedicated sub amp later.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #8
If the amp you use is the same as the one I used then you will get:
Front Left Base, Front Left Mid Range, Front Right Mid Range & REAR Right Base.
If you would prefer Front Right Base to Rear Right Base then swap 22 to 24, 23 to 25, 24 to 22 & 25 to 23. This is very easy to do.

I would take any wires out of 39,40 & 41,42. As these are speaker outputs, you don't want any shorts on them.

While you are there if you remove 6 & 39 (both orange) and connect them together, the sub should work.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #9
"The subwoofer should still work, if you're using the P38 head unit, as they are driven independently to the door speakers on the P38."

Yes and No. There is a feed from the head unit Sub output to the DSP (Pins 39 & 40) but it doesn't get used within the amp. The DSP generates the sub output by a D/A converter hanging off one of the DSPs and the output of the D/A is amplified and low pass filtered by a bunch of op amps before providing the sub output on pins 6 & 14. This was the bit that wasn't working on mine so I spent a lot of time tracing it. I think this is all part of the DSP 'effects' When you select 'driver' or 'spatial' the DSP modifies the subwoofer signal to create the effect. If it went direct from the head unit this couldn't be done.

On the BMW amp pins 6 & 14 aren't used so the sub won't work. It may be that the saloon versions of the BMW amp (or indeed the Disco amp) does have an output on 6 & 14 so the sub would then work.

I haven't looked at the circuit in my sub amp but the fact that mine works fine with only one wire connected suggests it is not expecting a balanced input. The sub output generated by the D/A is definitely not balanced (I looked up the chip) but maybe it does get converted by the op amps. It does seem a little pointless converting the sub output to a balanced output since the DSP and the sub amp are only about a foot away from each other.

All the above is based on what I have found in my car and the BMW amp I used. It may well be that there are differences in other set-ups.
 

·
LEGACY VENDOR
1995-2002 Range Rover P38A
Joined
·
4,218 Posts
"The subwoofer should still work, if you're using the P38 head unit, as they are driven independently to the door speakers on the P38."

Yes and No. There is a feed from the head unit Sub output to the DSP (Pins 39 & 40) but it doesn't get used within the amp. The DSP generates the sub output by a D/A converter hanging off one of the DSPs and the output of the D/A is amplified and low pass filtered by a bunch of op amps before providing the sub output on pins 6 & 14. This was the bit that wasn't working on mine so I spent a lot of time tracing it. I think this is all part of the DSP 'effects' When you select 'driver' or 'spatial' the DSP modifies the subwoofer signal to create the effect. If it went direct from the head unit this couldn't be done.

On the BMW amp pins 6 & 14 aren't used so the sub won't work. It may be that the saloon versions of the BMW amp (or indeed the Disco amp) does have an output on 6 & 14 so the sub would then work.

I haven't looked at the circuit in my sub amp but the fact that mine works fine with only one wire connected suggests it is not expecting a balanced input. The sub output generated by the D/A is definitely not balanced (I looked up the chip) but maybe it does get converted by the op amps. It does seem a little pointless converting the sub output to a balanced output since the DSP and the sub amp are only about a foot away from each other.

All the above is based on what I have found in my car and the BMW amp I used. It may well be that there are differences in other set-ups.
I'm not 100% sure on the balanced/unbalanced for the sub, as I've never actually put it on a scope to check, or dug that far into how the DSP amp handles the sub in the normal setup.

I know he non-DSP versions use balanced audio inputs to the door amps, but thinking about it more, you're probably right on the sub as when you look up the 'standard' outputs for those mini-iso connectors, then it looks like it matches up to a standard 'line out' feed, which would normally be unbalanced.

So with the BMW amp, you have all 4 doors being fed the separate low and mid/high feeds to their appropriate speakers (just to recap for myself!)

Nice work though! another inexpensive option to a stupidly priced DSP amp!
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #11
Looking at Marty's posts I think that anyone still reading this far should ignore my references to the Disco 2 amp as I had rashly assumed that it was very similar to the BMW amp but it would appear not to be.

I have ended up with an amp that has 8 working output channels - 2 per door. Tone, balance, fade, and subwoofer controls all work as expected. I no longer get the DSP options displayed.

Looking at the chips it appears to me (though I could be wrong) that each of the channels has some filtering on it (low pas for the base units and high pass for the mid / tweeters) so it's important to get the speakers on the right output. This sort of comes for free as the bass speakers are all on the larger pins of C0491. Whether there is any difference in the filter ranges between the DSP amp and the BMW amp I couldn't say but if you're concerned about this level audio quality then you've probable already replaced the stock system anyway.

Driving the sub direct from the head unit does have one potential drawback. On the DSP amp there is quite a heavy low pass filter in the sub output whereas the head unit output sounds to me to be the full audio range. (the orange wires in the picture above were used to feed the head sub output through the filters and it sounded much more what I expect a sub to sound like).
 

·
Premium Member
2002-2005 Range Rover MkIII / L322
Joined
·
3,622 Posts
Ok I did this today... couple things to note:

-BMW part 65.12 - 8 376 436 works also.
-Maybe the other BMW amp is stronger... but this one is pretty weak. It's loud enough when sitting still... but at highway speeds it's really not adequate. With that said it actually sounds good as long as you don't want to crank it.
-Connecting the two orange sub wires makes the subwoofer full range. This is easy enough to change with a passive crossover from ebay for $12
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #13
Interesting note about the volume, I've just tried mine and, although it's loud enough for my taste, I agree that it does run out of steam before my ears start to bleed. Are you saying it's definitely quieter than the DSP system? Your other post was asking about only using the front outputs from the head unit, did you wire the rear outputs up?

The DSP amp and the BMW use identical (2 x 40W) power amp chips so you in theory you should get 8 x 40W plus the sub. In practice it requires very careful matching of the gain and impedance to achieve this. I thought both the BMW and the P38 (and the Rover 75) head units were all basically Alpine Symphony units - internally the same but different face plates and connector blocks. Maybe I'm wrong and the output levels / impedances don't match too well.
 

·
Premium Member
2002-2005 Range Rover MkIII / L322
Joined
·
3,622 Posts
It's much quieter than I remember my old system to sound. No, I don't have the rears hooked up yet... but they won't make that big of a difference.
 

·
Registered
1995-2002 Range Rover P38A
Joined
·
121 Posts
Discussion Starter #15
Update

I agree that it is quieter than the original DSP amp. With the rear speakers connected it's loud enough for me. The DSP system increases the gain of the amp in response to the volume control (it sends messages over the Ibus to do this)whereas the BMW amp has a fixed gain. I suppose you could put a (4 channel balanced input/output) preamp between the head and the amp but that would be getting complicated and this was meant to be a cheap fix. In theory you could change the feedback resistors in the amp but finding the right op amps without a circuit diagram looks like a bridge too far for me.

The sub output from the head unit is full range, which is far from ideal, so I tried a cheap preamp / filter from eBay (around £5 from China!). Works as advertised but does seem to pick up a bit of interference. I'm also getting some distortion. I know my sub speakers are knackered but some of the distortion may be from the preamp. More work required.

A downside of using all five head outputs is that an aux in is more complicated (with the DSP system you can just feed the aux signal straight into the amp). I've ended up using the CD Changer input with an Arduino clone sending Ibus messages to fool the head unit. This works very well. Lots of info on the web on how to do this.
 
1 - 15 of 15 Posts
Top