Pardon my whining but I just finished the install in my BMW and I've got a problem.

The short story is that there is definate alternator whine coming from the headunit. The connectors at the head-unit are insulated and wrapped up - no chance of grounding out there. The grounding cables are installed at the amp's inputs and terminated at the ground (earth) terminal. The inductor is installed in-line with the ingition source for the head-unit.

If I pause the head-unit and drive around there is perceptable whine in tune with the engines RPM's. The whine get's louder if I turn up the head-unit volume.

The unit sounds amazing without the engine running above idle but this can't be tolerated for any length of time. I'm open to suggestions, recommendations or anything else that might help me out.

=-Clarke

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List 351, empeg 00045, 10gb, Amber

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 (avantg@btinternet.com 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

Yes it is an E36-M3.

Sounds like is the alternator that is to blame. Is there a third-party alternator that I could install do you think? What about inductors or orther noise supression at the source - across the alternators output leads?

I'll go for the best sheilded RCA's that I can find here in the states and replace the ones that I'm currently using. I ran the cables down the drivers side (LH side in the US) - your saying that the centre (your spelling :-) is a better choice as the wires for the heated rear screen radiate the alternator noise?> I've got nice cables but they aren't extra sheilded.

I don't have the room to add MDF between the amp and the car's mounting point. It's a Clarion 4302 and barely fits as it is. Perhaps I can rig something to prevent the amp from earthing - I'll have to sit and stare at it for a while.

What kind of spacing do I need between the inductor and the RCA's? Taking the glove box out is a pain in the a** but there is much more room there for think like the inductor.

So: best sheilded RCA cables I can find, move the RCA's to the cars centerline on the way to the amp, isolate the amp from chassis if possible, HD inductor in-line with the amp's power supply, tie all the grounds back to the termination for the rear window heater wiring and if all that doesn't work panic. :-)

That's alot more work than I wanted to do darn it.


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List 351, empeg 00045, 10gb, Amber

empeg #00001 is in a E36 (320i) - the whine isn't too bad: it's there, but you can't hear it with music on/when you're moving. On his install, the cables go down the side of the car too.

One thing I noticed on my honda install (which I did at home) is that you really shouldn't bunch up the phono cables (when they're too long) right next to the empeg's power filter - just changing this got rid of 90% of the noise. Ideally, don't bunch up the cables at all, just use ones the right length :)

Hugo

I finally got my install done yesterday, (serial # 00031). The unit is very stealthy and can barely be seen through my semi tinted windows, very nice!

The sound is just as good as it was when hooked up to my home stereo, that is until I turn the car on. :(

I have the same symptoms as described by Clark above. The EMPEG is installed in a 1995 Audi 90 V6 and attached to an Alpine MRCF303 4 channel amplifier. I have bypassed the factory amplifiers for the rear speakers. All the install directions were followed to the tee by Tweeter here in Boston. The unit does have a hiss even when attached to my amplifier at home and paused, but this is easier to ignore than the engine noise. We found that when we hooked the ground wires to the Amplifier ground there was still a lot of noise. But when we hooked them to the outside of RCA output of the amp the noise was reduced. This did not make much sense to us but did make the unit usable in the car, other than the engine noise.

Any help and pointers would be appreciated.

---
Kamau Wanguhu
BORGcube Systems
kamau@BORGcube.com

Well here's the update.

1) I made sure that the inductor was as far away from the RCA's as I could get them.
2) Put in triple-shielded RCA's and tied the ground of the 3rd sheild to the Amps ground post
3) Ran the RCA's down the car's cent(re) line to the amp
4) Ran a new ground cable from the amp to the empeg

Results: less money in the wallet and a minor decrease in the amount of alternator whine present. Still noticable with music playing and while driving darn it. I don't have room to put the amp on an MDF board and seal up the rear paneling so that's not an option.

At this point i it looks like I'll be looking for an alternator noise suppression kit. I'd certainly welcome any suggestions anyone has to offer at how to reduce the whine that's present. I'm pretty unhappy at the moment. I'll keep plugging away, I don't have a choice after spending all this money.

Hugo, how about revisiting your output stage design and consider something like driving differential outputs with an extension harness that can be located with the amp. That would make sure that no noise can be induced and the floating grounds wouldn't be an issue.

=-Clarke

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List 351, empeg 00045, 10gb, Amber

Here's a suggestion I had some success with. I have a TR 6 with a 60A Lucas alternator. It's not an open-cage alternator like the newer high-output, switched regulator alternators on newer cars - but nethertheless it produced whine on my radio (as an aside, I am not sure I approve of switched, rather than analogue, regulators in an alternator).

The TR 6 bonnet is extremely large, and hinges forward at the front. I was told that the whole panel is not very well earthed due to the weediness of the connection at the two hinge pivots, which means that only the two inner wings were acting as part of a decent Faraday cage (magnetic field shield). What I did was bought two large, flat-braided battery earth straps from Halfords, and connected my alternator casing to ground with one, and with the other, crossed the hinge on one side of the bonnet to earth the panel permanently to the inner bodywork. I also checked that the battery earth was properly grounded to the bodywork by grinding off paint around the bolt point for the standard earth strap.

Bingo! No more noise; I took the strap off the alternator later on, and it did not make such a big difference, so I would say a bonnet earth to fully cage the engine compartment and an improved battery ground might help if my experience is anything to go by.

I drove a BMW 316 and a 525 for a while a few years ago, and both cars had radio interference problems, which the dealer could not sort out. They have always been (and apparently remain) troublesome. It seems worse on radios with high-gain pre-amps from the tuner.

Clark;

I had posted that I had the exact same problem when I tried to use an Alpine Amp. During the install (which lasted about 5 Hours) we were plagged with the engin noise problem. We tried different brands of Alpine Amps, we even tried a brand known as Eclips which supposedly is made for the Toyata line of cars. We had noise in all cases.

In frustration my installer suggested we try a Kenwood 4 channel Amp (KAC-848). We unplugged all the cables going to the Alpine and connected them all to the Kenwood, HEAVEN! It was so quite and clear, I was reassured that I did not waste my money on the EMPEG. If you can lay your hands on one of these units, I would say by all means use it.

The best thing about the Kenwood is that you do not even need to use the cables that came from EMPEG to ground the RCA cables to the AMP chasis. The Kenwood seems to take a floating ground and do the right thing.

I have been a happy camper for the last week, driving around town with a silly grin on my face and ... but I digress.

Hope this helps.

Kamau Wanguhu
kamau@BORGcube.com