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Stupid Buzz! (I have tried everything)

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  • Stupid Buzz! (I have tried everything)

    I know everyone is probably tired of posts about this topic, but I have searched and searched and tried everything but I cannot solve this problem. My computer in my car worked great with a very small but tolerable hum, until just recently when I installed an amp to power my speakers. Now I get a very loud buzz even with the volume all the way down. The buzz only occurs when the computer is turned on; when the inverter is on without the computer plugged into it, there is no buzz at all. Also, the buzz is louder in the right speaker than the left. I have both the power supply of my computer and my 140 watt inverter grounded to the same spot as my sub amp and speaker amp. I have tried separating the rca and speaker wires away from all wires related to the comptuer, but that had no effect on the buzz. Also, I tried plugging the computer into a surge protector and then into the inverter, and this decreased the buzz somewhat, but it was still loud. The audio of my comptuer is connected to the head unit via rca cables plugging into the aux input on my head unit. That's all the info I can think of, please help me somebody!

  • #2
    have you tried grounding the motherboard?


    • #3


      • #4
        Ground Loop Isolator
        CarPC Stolen. Starting over.
        Ne1 recognize the avatar?


        • #5
          Originally posted by PatO
          Ground Loop Isolator
          he speaks the truth. $15 radio shack. go now.
          Car: 1999 Dark Green Mustang GT Coupe
          Audio: Alpine HU, JL 6ch Amp, JL Stealthbox and XR series components.
          Player: Empeg for now; something custom later.
 - Custom built laptops!


          • #6
            Have you tried removing the filter, in the AC power supply? There was a link on here about it. Works awesome.

            I change my amplifiers, signal processors all the time and have also encountered "unsolvable" humming noises, that cannot be rectified by grounding, wire routing (even with the power supply fix).

            In some cases an RCA ground isolater worked, sometimes it didn't. Sometimes a 12 Volt power supply filter (sold for car stereos) worked, sometimes it didn't.

            Each case is different, and you'll just have to hunt it down, by trying various ideas.

            I can change a single component in my setup (four amplifiers, 3 signal processors), and I'll have to basically start from scratch troubleshooting any noises.

            Oh yeah, make sure your gains are setup properly on the amplifiers. Those things are not volume controlls.

            Best Luck......Sdude.


            • #7
              I went and bought a ground loop isolator and it didn't change anything. I don't know how removing the AC power supply filter would change anything because it didn't need to be removed before I got this new amp. Does anyone else have any suggestions?


              • #8

                Guy, I had the same problem, It was my inverter, I first used this old 140 watt inverter I got from work and she hummmed like a hoe, I went to walmart and bought a Modified sign wave inverter I bought the big *** 1 for 40.00 or so. that took out the humm all toghter. Its Your inverter.


                • #9
                  I'm pretty sure it's not the inverter, #1 because it worked fine before I added the new amp, and #2 because there is no buzz with the inverter on by itself, only when the computer comes on.


                  • #10
                    smoldyr-- You have to remember that an amplifier is there to amplify, so as you said in your first post, there was a low hum to start with now it's worse. And as for your statement about no buzz with the inverter on but comp off, that is going to happen because the amp isn't getting an input signal...

                    Try what Jay87T said or look at a way of getting rid of the inverter...
                    Such is life....


                    • #11
                      Alright, I have done hours of testing and have pinpointed the problem, but I don't really know if there's a way to fix it. The buzz starts when I ground the power supply of the PC, even without my RCA cables plugged in, there is still the buzz. You would think, well duh, just don't ground it then, but if I don't ground the power supply, the electricity will flow out through my soundcard when I connect the RCA's the buzz will be even louder. Does anyone know how to solve this problem or what is causing it?


                      • #12
                        try a different power supply for starters.
                        You could have a faulty ground connection in the power supply.

                        Also turn down the volume in windows or whatever os u are using. Sound cards push a lot of power. I didn't realize this until i plugged in my computer. I ran the sound card to my amps, and damn near blew the speakers because i had the volume slider all the way up.

                        Also how close are the RCA's to the invertor, my friend had his close to the invertor and it caused him to have a humming noise.
                        Also are you using sheilded or non sheilded RCA's

                        Sheilded RCA's will pick up noise emitted from the inverter (humming from the fan).


                        • #13
                          Then try not grounding the PC power supply AND using the RCA ground loop isolator.

                          And did you say that you get the hum even with the line output unconnected? In that case I would think that the amp is way too sensitive to power supply ripple & noise or so. (Or the inverter is producing way too much garbage on the power line)

                          Some more test scenarios; disconnect the PC (no hum) and load the inverter with something stupid, a lamp or so.
                          Or; keep this configuration but connect the inverter to a second battery so it gets an isolated 12V source (but keep the grounds in common)

                          Have you also tried the ground loop isolator between the HU and the amp?

                          Just some hints...

                          white bream
                          working on a trilogy: CARGO - UNIGO - MERGO
                          CARGO = the Car Computer
                          Intel Celeron M, [P]SDC, uBlox GPS, GPRS, WLAN, Silabs FM, RDS, TMC,
                          Dual-audio, Onecable TFT, Microsize: 45 x 108 x 168mm (1.8 x 4.3 x 6.6")


                          • #14
                            putting the ground loop isolator between the amp and the deck won't solve anything. He's already isolated the problem as being between the computer and the inverter, not from the deck back.

                            Try what henkbliek said and run something else off the invertor.

                            I would really try and borrow a friends computer and try it out. See if that makes the noise go away. If so i would try another power supply in the computer.

                            I've probably spent $40 on ground loop isolators within the past year to get rid of a hum and alternator whine.

                            None of the isolators worked, in fact they made the problem worse, using a ground loop isolator isn't the answer to everything although that is the first thing everyone wants someone to try.


                            • #15
                              I was having pretty much exactly the same problem and found out it was just my really cheap and nasty amp. Long story short, I bought a good amp and it is great, even with my 300 watt inverter right next to it (although the rca inputs are routed away from all my power cables :-)

                              And yeah, I agree with psycotic, i too have bought many noise suppression devices and they suck!

                              Hope this helps
                              Mitsubishi Lancer Hatch
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