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Speaker noise issues caused by PC audio out any Solutions?
bluethunder:
Seems alot of PC built in audio is fairly noisy.
A cheap fix is a PCI sound card, always are better isolated from noise.
RamjetR:
Ground loop issue for sure!
Are you running a separate power supply for your Amp on the same AC circuit as your PC? Meaning, do they share the same common earth pin in the AC plug?
Reason Case point:
I have a driving cab with an ATX PC powersupply powering a 5.1ch TA2020 Audio Amp: http://www.ebay.com.au/itm/5-1-Channel-TA2020-Audio-Amplifier-Kit-Class-Board-/230652735126?pt=AU_Electronics_Audio_Amplifiers&hash=item35b3f96e96
For the sake of a test, used a laptop to inject the audio/video and to control the PacDrive LED controller for the 5V lighting (buttons) and used the 12V ATX power from the same supply as the audio amp for the 12V LED strips.
Problem was this, every time the LED's pulsed there was a MASSIVE thump in the speakers.
Result was the following; The Laptop uses an isolated powersupply which mean't there was no common earth return back to the ATX powersupply from the PacDrive. The current for the 12V LED strips had to travel from the PacDrive, down the USB cable earth, then back up the Ground pin of the Audio cable (because it had nowhere to go? Kirchov's Law right!) and through the 5.1 amplifier ground and finally back up the Ground wire to the ATX powersupply. This would raise the ground reference, which would appear as DC injection on the audio signal. It would be amplified and appear as the DC THUMP! on the speakers!
Now I never had this issue with my normal cabinet. But the difference was that the PC supply and the external ATX supply both share the common earth ground from the AC adaptor. This was my only earth link but enough to equalise all the grounds to the same potential. Hence no problems... but once I went to isolated powersupplies, it was a world of trouble.
This is why checking your ground wires and earths are critical.
Make sure that if your using multiple powersupplies (1 in a PC and another for other 12V/5V stuff) they share the same ground on the AC powerboard, or better still, tie a ground link wire between the chassis of both 12V ATX powersupplies (NOT THE CRT CHASSIS!!! They can often be live chassis!).
Take the time to sketch out how your cabinet is wired in terms of the DC and the audio, LED controllers, PC etc... block diagram would be sufficient. Post it up and we'll take a look at it for you.
Ramjet :)
kahlid74:
As has been stated by several before me, you've got a groundloop. You need to identify how the power is being provided to your amp and then identify the power in your PC as well. If you plug the amp into one outlet and the PC into the other and you're still getting the static you need to identify why your PC isn't properly grounding and is instead grounding into your amp.
Every time I've seen these problems it stems from either a bad PC Power Supply or some type of light on the bulb/lighting device on the line that's making this pissy.
yaksplat:
I solved this by adding a $50 USB creative sound card into my cab. It works great and has more than enough outputs.
dave197878:
The amp and PC is running off the PC atx power supply (12V Yellow and black wires). I plugged in head phones to the audio jack to test and theirs no noise. So at this point i figured it was the amp creating the noise but as mentioned above with the same power supply and plunging an mp3 into it as the source it works fine.. So the ground loop only appears when both the amp are plunged into the power supply and pc audio jack. Only when one of these factors is removed the issue seems to go away.
So yes its a ground loop issue.. I have a ground loop isolator 3.5mm in my car for my sirius radio I use it to remove the alternater sound so I gave it a try on the PC out and it worked...
Anyone see an issue with this fix.. it is a bandaid fix but it does work. Should I worry about the ground loop causing any other havoc? Can it effect the crt or do any damage? TY for the help every one.