I recently got a second hand ADS830X amp and hooked it up to 4 Boston Z6. When I turn the ignition switch one notch, the system sounds fine, but when I turn it one more notch (when all the lights on the dash lights up) or when the engine is running, there is a constant humming noise, sort of like a mosquito flying around. It's noticible in between songs. The techincal guys at the shop tried everything possible to cut the interference but nothing works. They say there's something wrong with the amp cos' when they unplug any one of the RCA input, the noise is gone. We hooked up an Alpine amp to test and there was no noise!
If I have to get a new amp, what do you guys recommend? Arc Audio 4150-XXK, Zapco C2K4.0X, two JL 300/2 or Soundstream HR4. I would like at least 4x100W. Thanks!
They are very far apart, the battery is in the boot and I ran the RCA thru the middle of the car avoiding all electrical wiring. The RCA are MACROM cables with all the meshing & insulation.
We even test it by running the RCA outside the car!
there are alot of options here, ill try to list them, it could be alternator whine , if it varies with engine speed, it is most likely alternator whine. as the alternator converts engine power to electrical power it produces a tone based on frequnecy. The frequency varies with engine speed, in which the higher the rpm the higher the pitch of the noise. IF the noise IS present while your car is not running(you already said its not) then it CANT be alternator whine, so this is still a possibility unless its there while the truck is not running.
niext possible noise is "radiated" noise, this is often called EMR(electromagnetic radiation) in this it doenst travel through the power wires, but is trransmitter from the noise generating wire into whatever wire or circuit is withing the radiation field, its pretty difficult to correct because the path it follows is invisible. It is solvable and is not a reason to live with the noise. you can use a device called a "noise sniffer" or a EMR detector to find the hot sponts in the vehicle that are radiating the noise, for example, one of the most commen noise modes is when a head unit picks up the EMR that is radiated from the factory wiring in the dash. In this case you can use the head unit as a noise snifer since if you were to unmount the headunit and pull it gently away from the dah while it is playing you would notice the noise fading out. That meanst eh noise is being radiated from the surrounding wires and moving it away a few inches corects the problem, then you can jsut find the offending wire, usually the biggest gauge wire carrieing the current levels large enough to create a big noise field. Almost anything in the signal chain can pick up radiated noise. Power and preamp cables, processors, corssvers, speakers. Last is "ground loops" if you consider what is happeneing with a ground loop, it makes understanding easy, each component has a differnt lenght of of power wire and draws a differnt amount of power. That means that the coltage dop on each power wire is not exactly the same, So if your headunit is recieving 12.2 colts after line losses and the amplifier in the trunk getting 11.8 colts after its line loss the difference is .4 volts. This differnece can try to baliace itsself out by taking a shortcu through the preamp cables. the preamp cables should be carrying no more than the audio signals, so when you add alternator wine, it adds to the music, basiccaly just pissin you off mo and mo. lol To deal with a ground loop you need to find out where the loop occurs, If the coltage is tring to return to the engatice terminal of the battery by traveling though the body of the vehicle and the preamp cables there will be a difffernec. By installing a ground loop isolator, you can ofter add enough ciruit isolation to force the DC to travel only along the ground wire and the cahssis of the truck, while the musicle signal uses the preamp cables.
Thanks for the detailed explanation. I know it's defintely not alternator whine cos' we got rid of that. The hum is constant in tone and volume at any engine speed.
It has to be EMR but why is it when we tested it with a new Alpine amp, there is no noise? Is the ADS too old?