Amp connections

[Alan W]

As discussed on a previous thread, the factory fit footwell amp has two power feeds, one constant live and a switched feed which tells the amp that the head is on and powers it up and thanks to information provided in that thread I now know what wire is for what.

I have now got a new replacement amp which I wish to install as part of my upgrade which retains the factory head unit... but just need to clarify the power connections as there was no wiring diagram in the box. I phoned up the supplier and they said that they do not supply instructions as the amp should be installed by a qualified professional fitter who would know how to wire it up. Thanks for nothing!!!!

Okay. heres a photo of the business end of the amp and you can see the power connections top right:



So left to right there is R then earth then B+

It came with a plug and wiring loom and the B+ wire has an in-line fuse in it

So I have to connect the R and the B+ to my cars constant live feed and the head switch feed, but my problem is which goes to which????

Anyone ideas... no correction... anyone know for certain?

Many thanks

Alan

[Gazza]

I would suggest searching online for the wiring diagram for the model you have bought

[Alan W]

Okay, may have now found the answer to this... what a wonderful thing the internet is

B+ is the contant power feed to battery positive

R is short for REM which is the one that connects up to head and sends a to amp to turn on when head is switched on.

Mission accomplished

[Robert T]

And REM is short for "Remote", which is what I was going to suggest.

I suppose it could have been Rapid Eye Movement or an indication that you can only play R.E.M. CDs on it.

So you have both a permanent supply and a switched supply from the headunit which will likely operate a relay inside the amp to actually power it up, with high current being taken from the permanent supply rather than the low-current REM line, just as the BMW unit was wired. Depending upon the wattage of the new amplifier, the original wiring may be enough, or it may really want you to go direct to the battery with an inline fuse. I'd need to check the ETM to say whether the original wiring is a permanent live or switched with the ignition - I would have thought either would be acceptable for an amp - you just need to watch how much current it wants to draw if you do use the original wiring, as it will be a gauge of wire designed for the job and fused to match.

Cheers R.

[Alan W]

Cheers Robert

Although the business head unit is not brilliant by todays standards, I really want to keep it as it looks 'right' and it has that thing where the volume increases with speed.

I like that, especially when the roof is down and you pull up at the lights as you dont have to reach for the volume knob to stop everyone frowning at you!

There are a lot of installation location and quality issues with the OEM speakers and I don't rate the OEM amp which looks like a kid built it as a science project.

This is my plan...

Replace footwell woofers with Pioneer 5.25" dual cone speakers @ £20

Replace rear speakers with Pioneer 4" dual cone speakers @ £25

Replace OEM amp with a modern compact 2 channel amp which will drive the front footwell speakers @ £28

Install egg box soundproofing in all speaker cavities @ £18

With this set up the rears and door tweeters wont be amplified.. but I only want these for 'ambient' sound with the lions share of the work being done by the amp and footwell speakers. If the tweeters sound like they need a bit more power I will upgrade them and splice into the footwell speakers and use a choke.

I am fairly sure that installing the above will give a much better sound and all for under £75.

The amp is tiny (palm sized) and should easily be able to lose it somewhere behind the glove box.

I now have all the above and will be fitting when the weather is nice and will upload step by step photos of the installation.

Just hope I haven't wasted my money...

[David]

Hi Alan,

I'm very interested in seeing your write-up...
I am, what some may call, "challenged" when it comes to electronics (being heavily colourblind never helps!) so, by all means, please add as much details as you can!

GL with it all, I hope it goes smoothly.


Sent from my iPhone using Tapatalk - now Free

[Robert T]

Alan, you have the same speaker setup that I currently have in my car, and you have to remember that this was the bottom of the range option - the Harmon-Kardon setup had more speakers and a sub-woofer with a separate amp in the boot for it - it was quite an expensive option if I remember rightly. Stock speakers are not that great, but my BMW headunit was replaced on day 1 by the Pioneer unit I had in my previous car (mainly because it had a 6 CD multichanger with it), so I've never really listened to the one properly. Road noise in the zed quickly overcomes any sound system, so I've never seen the point in spending too much money on such things - it does for what I want in the car. If I wanted to listen to music properly in the car, I'd take my home hifi with me, but the speakers are 4ft tall and wouldn't fit in.

Good luck with your project. Be interesting to see how you get on.

Cheers R.

[Alan W]

So here's the components for the above upgrade I am going to try on the standard OEM audio system...

There's a roll of eggbox acoustic foam which will be installed into the speaker voids which will hopefully prevent that 'boxy' wooden sound, and then there's a set of pioneer 5.25" dual cone speakers for the front footwells, and a 4" version of the same to replace the rear speakers. The leads to the left are an adaptor to convert the business head speaker output wires into RCA fittings so I can connect to the new amp, and the leads to the right are just extentions. Middle front is the amplifier which will replace the factory fit amp:



And here's a close-up of the amp, its tiny and is smaller than my hand:



As soon as there's a nice weekend I'll start installing..