Clarke,

Is this an E36 3 series by any chance??

If so, then they give us nightmares on a regular basis, no matter what unit you're installing. Anything with an internal amp works OK, but the second you go for external amplification, then you invariably get whine problems. The later 5 and 7srs also give more than their fair share of problems, but not to quite such an extent. The whole problem stems from the alternators fitted - they're a huge air cooled unit, all but impossible to suppress, and they radiate just enough AC right through the entire wiring loom to cause major problems with RCA signals.

To get around the problem, some things worth trying:-

The RCAs need to be the best screened ones you can lay your hands on. If you're in the UK, then Autoleads do triple screened leads (let me know if you need any help tracking down your nearest dealer) - these should be considered the minimum standard. Better still are triple screened leads, with an outer screen you can ground either end. These must run down the centre of the car - the heated rear screen feed runs down the n/s and radiates more RF than you'd ever believe, and the main battery feed runs down the o/s, assuming the battery's in the boot on your particular model. A portable radio, set off station on AM, can help here - use it to 'sniff out' the best routing for the RCAs - as you move it around the car, you'll be able to hear where the noise problems gets better or worse.

Earth everything, Empeg included, to the main earth point in the rear of the car that the heated rear screen aerial amplifier earths to. This varies slightly according to model, but if you remove the nearside rear quarter trim panel (passenger's side on UK RHD cars, presumably it's in the same place on LHD), it's fairly easy to trace the cabling back.

Mount your amp(s) onto an MDF or similar board to make sure it can't earth via it's chassis.

A heavy duty inductor in the main amp power feed can help in some cases, although it's more common for the RCA cables to be the main source of noise.

Make sure the supplied Empeg power filter stays well away from the RCA cables behind the mounting cradle - if you remove the glovebox, then it's possible to pull all the Empeg power cabling away from the RCA cables completely - it might help to remove the plastic P-clip from the back of the cradle so you've got a bit more movement on the cables - just make sure they're not strained at all.

If all of that doesn't help, then a 1/2 - 1 farad cap on the main power feed off the alternator can help in some cases - speak to your local ICE dealer for more advice on this - you need to be a bit careful about recharging them if the battery's disconnected for any period of time.

Hope all of that's of some help. If you don't succeed in reducing the noise to an acceptable level, feel free to drop me an email ([email protected] outside of work) and I'll see if I can come up with any more suggestions.

Dominic





Cambridge Car Audio
http://www.cambscaraudio.co.uk