Discovery 2 Amplifier Bypass

td5notalive · Apr 2, 2018

Morning all.

has anyone found a diagram showing the pinout for the factory amp

found a lot of wiring diagrams but no diagrams of the actual connector

Mine sounds awfull with a new modern headunit, planning to bypass and re-use the amp just for the twin rear door subs

sierrafery · Apr 2, 2018

Everything is in RAVE you just have to learn how to use it... on the diagram you see the circuits then the connector shown at the amplifier e.g. C0491 is shown in the "electrical library - connector views"

brian47 · Apr 2, 2018

The usual reason for the audio to sound liked crap after the head unit has been changed is that the input to the amplifier is being overloaded.
The head unit needs to provide a "low level" feed to the amplifier.
What was the reason that the head unit needed to be replaced? Not enough bling?

td5notalive · Apr 2, 2018

Replaced the Alpine cassette with a Bluetooth Kenwood unit so I can have handsfree and music, worked really well but sounded awfull..

decided to do it the hard way, traced wires from headunit iso plug and used multi meter to find each speaker

in my 2001 ES with highline audio the rear door pairs come to the amp as one pair per door, the front doors pair and pilar tweeters are individually wired to the amp

All gutted and re-connected and sounds so much better. Think the amp has internal crossovers that are pre set and the modern head unit sounds awfull

Dumped the rear door sub as it gave me headaches ( I wear hearing aids) even with bass down

brian47 · Apr 2, 2018

td5notalive said:
Think the amp has internal crossovers that are pre set and the modern head unit sounds awful

There are two different amplifiers which could be fitted to the D2; Lear and Harmon.
The Harmon amp feeds the front door speakers and the "A" post tweeters in parallel, relying on the frequency responses of the speakers to provide some sort of a crossover effect.
The Lear amp does feed separately to the two speakers, front door and "A" post tweeter.

Yoguko · Sep 24, 2018

brian47 said:
There are two different amplifiers which could be fitted to the D2; Lear and Harmon.
The Harmon amp feeds the front door speakers and the "A" post tweeters in parallel, relying on the frequency responses of the speakers to provide some sort of a crossover effect.
The Lear amp does feed separately to the two speakers, front door and "A" post tweeter.

Reviving an old thread...

How noticeable would it be to change the Lear amp for the HK amp, while maintaining the High line (Phillips speakers)?..
Would it be simply a question of different frequency responses from the HK vs Phillips speakers? And how noticeable would that difference be?

brian47 · Sep 24, 2018

Yoguko said:
Reviving an old thread...

How noticeable would it be to change the Lear amp for the HK amp, while maintaining the High line (Phillips speakers)?..
Would it be simply a question of different frequency responses from the HK vs Phillips speakers? And how noticeable would that difference be?

It's not the oldest thread we've seen today.

Regarding changing the amplifiers and the resultant frequency responses, I wouldn't know, but do bear in mind that it's a Land Rover Discovery, an aluminium and steel box on wheels not some finely tuned audio theatre.

Yoguko · Sep 25, 2018

brian47 said:
It's not the oldest thread we've seen today.
Regarding changing the amplifiers and the resultant frequency responses, I wouldn't know, but do bear in mind that it's a Land Rover Discovery, an aluminium and steel box on wheels not some finely tuned audio theatre.

Very true Brian...
I'd hazard a guess that the bass would probably be much better with the HK amp. Maybe not so much L/R separation on the mid and highs, but I could certainly live with that.

I'm extremely jealous of my mate with his fancy HK system /Es Premium), and the sound is so much better. I noticed the connections to the amp are the same as mine, so I might just borrow his amp.

Trying to keep my original stereo, so I already have a hidden DAB system and a nice Parrot hands free installed. I'd be set if the sound from the speakers could be just a bit fuller.

Thanks Brian.

brian47 · Sep 25, 2018

There are a number of faults which can afflict vehicle loudspeakers, usually the effects of damp air causing rust particles in the magnet air gap, or causing damage to and distortion of the paper cone.
Age can also cause the outer edge of the cone to become detatched from the main frame, either by the glue coming unstuck or the edge of the cone tearing possibly due to overdriving it. Overdriving can also damage the centering spider for the speaker coil.
While the amplifier will probably have some effect on the frequency response of the whole system, I would say that major audible differences are more likely to be problems with the speakers themselves.
Consider also the old adage, "Crap in equals louder crap out", and I'm not talking about *Rap with a silent "C".

I presume that the head unit is the Alpine R990, do you have the owners handbook for it?
It shows how to set the bass and treble as well as the R/L stereo and front/rear fade.

Yoguko · Sep 25, 2018

brian47 said:
There are a number of faults which can afflict vehicle loudspeakers, usually the effects of damp air causing rust particles in the magnet air gap, or causing damage to and distortion of the paper cone.
Age can also cause the outer edge of the cone to become detatched from the main frame, either by the glue coming unstuck or the edge of the cone tearing possibly due to overdriving it. Overdriving can also damage the centering spider for the speaker coil.
While the amplifier will probably have some effect on the frequency response of the whole system, I would say that major audible differences are more likely to be problems with the speakers themselves.
Consider also the old adage, "Crap in equals louder crap out", and I'm not talking about *Rap with a silent "C".

I presume that the head unit is the Alpine R990, do you have the owners handbook for it?
It shows how to set the bass and treble as well as the R/L stereo and front/rear fade.

It is the R990 that I have installed and I went through the trouble of checking all the speakers for damage while swapping a knackered mid and one tweeter. They're all visually ok, with no tearing or corrosion. I tweaked the treble and bass a bit, as well as a bit of bias to the rear speakers.

Sound through the Parrot is much better, presumably because it has its own mini amp in there and it's easy to tweak the equalizer. Comparing radio broadcast sound with my other mate's Disco, who also had a high line system, there isn't much difference to mine, but a marked difference (specially the bass) to my other mate's HK system.

High and mids are perfect, but it lacks some punch. Music comes through loud, rich and clear, but not much bass to it (and I don't listen to C*Rap "music" either).

Edited to add that when I say there's not much bass to it, I mean it's a "dry" bass, not very complex or lingering, for lack of a better description...

cosden365 · Feb 28, 2021

Yoguko said:
Very true Brian...
I'd hazard a guess that the bass would probably be much better with the HK amp. Maybe not so much L/R separation on the mid and highs, but I could certainly live with that.

I'm extremely jealous of my mate with his fancy HK system /Es Premium), and the sound is so much better. I noticed the connections to the amp are the same as mine, so I might just borrow his amp.

Trying to keep my original stereo, so I already have a hidden DAB system and a nice Parrot hands free installed. I'd be set if the sound from the speakers could be just a bit fuller.

Thanks Brian.

I've just come across this thread, and realized I'm in the same situation with my friend

. Have the high-line Philips system with a Lear amp and the opportunity to buy a HK amp (maybe even the HK speakers). Did you made the swap after all? If yes how did it work, did you have sound in all the speakers? cause from my understanding from the electrical diagrams the harnesses differ from Lear to HK even though they have the same connector. Thanks for your time and sharing

Stanleysteamer · Feb 28, 2021

I'm bookmarking this thread as i have 3 discos with varying systems from the original Disco 1 Anniversary with a bust CD player, that sounded brill even though the speakers on the sub needed replacing, to it's replacement, Blaupunkt, with a 12 disc CD player but no connection to the sub, which is a pain.
Both my other D1 and my D2 have replacement systems, which sound sort of OK, but then I am not a specialist and don't understand a lot of the tech terms.
It was so nice to read exactly what it is that screws a speaker, re the rust for instance.
I do miss subs though.
Please, all, keep up the good work and I am sure I am not the only one who appreciates this thread and is learning from it!

ronsealdeath · Feb 28, 2021

I did this and blew up the HK amp in about 3 months of use. I think one line of the HK was trying to run speakers in parallel which loads up the impedance and fries an amp.

In my opinion you should re wire the speakers and use the HU amp.

Discovery 2 Amplifier Bypass

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