Howdy.. I just finished an install in my 95 M3. I had a blaupunkt pa4100 amp in there, which seemed to be defective.. but I'm running into problems with my new one as well..

When I start up the car or turn on the empeg with the car off, there is a very loud buzzing noise (sounds like a bee right in your ear) that comes mostly out of the front speakers. When I started the car, it would buzz, and the buzz would slow down in pitch over about 10-15 seconds and then go away entirely. Note that the intensity of it did not fade, just the pitch.. and once it slowed down enough it dropped off. This is independant of which channel is hooked up to which. I finally traced it back to the gain settings on my amp. I turned the gain down a tad and the noise went away entirely. However, I inched the gain back up to where I wanted it (and tested in between runs), so I had the gain where I wanted it, and no buzzing! I let the car sit for awhile, then started it back up, and the buzzing is back! I don't want to turn the gain down any, because the max output from the system would be too quiet! The amp should have MORE than enough power to run the system, so that's not the problem.

Any ideas what the cause of the buzzing is? Is it a noise from the empeg that's being amplified? The noise seems to occasionally pop and fade out from one side speaker, so it's not totally consistant, but seems pretty solid otherwise. Is it from my RCAs? Why on earth does this fade away after the car's been running for 20 or so seconds? Is it perhaps related to battery voltage? IE, either turn down the gain or crank up the voltage going to the amp to get it to go away? Maybe this means a power connection could be better.. ?

Anyway, any ideas you can provide would be great. My last amp had a blown rear channel, I don't think I did it, but I suppose I could have.. I'm finally getting the system running essentially right, except for this buzzing noise! Don't want to blow another amp..

- reid

It sounds like a ground loop, or possibly a mistake in the wiring. Please click on this link and read what it has to say.

Another thing to consider: Perhaps you're simply turning the gains up too high. Your player should be able to be turned all the way up to 0db (maximum) and you should be able to listen to it comfortably. If the loudest you ever crank your player is -15db, then your amp gains are turned up 15db too high. The proper procedure for adjusting your amp gains is discussed in the link I just gave, above.

what he said.

also, where are you mounting your amp, and what speakers are you using? Did you have the HK system? give me some more info, cuz i did my install in am m3 about 6 months ago.. and i uninstsalled it all about 1 month ago.. so let me know

tony one other question, uhmm, odb should be the comfortable level of the loudest.. my rear gain is all teh way down and the front is about 2 clicks up (staging reasons) windows up i listen at -3 to -5 windows down i goto 0 or maybe +1.. i really don't want to use the -12 db cut on my amp and gain up, (heat issues) since summer is coming and it's under a seat, so the way i am running it shoudl be fine right?

The purpose of adjusting your amplifier gains is so that you can maximize the signal-to-noise ratio and prevent noise in the system, while maximizing its dynamic range. If you are happy with the S/N ratio and the dynamic range of your system, then your gains should be fine.

No, my gain's actually a tad lower than I'd like. turning it down seems to make the problem go away though. I unplugged my RCAs and it still did it -- definately not an empeg problem.

Rockstar, no, it's a 95, no HK system. Empeg plugged into stock wiring, RCAs up center tunnel to trunk, into blaupunkt PA4100 4ch amp. Front channel going to the crossovers mounted in the trunk, then using factory wiring to go up to my focal 130k front speakers. Rear channel bridged running in parallel to my jl audio stealthboxes. Amp set to 3ch mode, crossovers set appropriately.

I'm grounding my system to the battery. Where did you ground yours? I'm going to try a different ground.. my current thinking is for some reason the battery is a poor ground point (maybe because the potential difference between the - term of the battery and wherever the deck grounds to is too high).. so when the car first starts it sucks power and the difference is noticeable.. once the car runs for a few seconds, the voltage stabilizes and all sounds good. The battery should be a good ground point, but.. maybe it's not. I'll try different ground points sometime.. maybe tomorrow. For now the system works flawlessly, just sounds like crap and is annoying when it turns on

I'm hoping this isn't what blew my last amp -- it was getting very hot driving just the front speakers, and this one is not driving the fronts AND the subs.. plus the noise from the rear channel on the old one (Before it went out completely) was different from the noise I get thru this amp..

no burning smell from this one yet either

- reid