Learn and fix ground loop noise

14.4vTech · 06-09-2004, 09:50 AM

The elusive hum or whine how to track it and learn about it

I wish this sight was around 10years ago, but my years of experience can tell you this is damn good reading, accurate as well. simple google search finds this page: http://www.epanorama.net/documents/g...oop/index.html
After you read the intro theres a niffty little section on application and problem.

Recommended to anyone here, people asking and answering questions here can learn alot our add to their existing knowledge.

fantomas · 06-09-2004, 10:10 AM

awesome find! thanks...this will surely help out a lot of people

cyber · 06-17-2004, 08:50 AM

Another good practice to remove interference is to run your RCAs->amp under the molding on the opposite side of the car from the power wire->amp.

philstuf · 07-03-2004, 08:55 PM

In addition, you can help eliminate potential induced noise in cables by routing them 90 degrees to any cable they cross. Of course, its sort of hard to route the audio signal 90 degrees from ground, as the entire chassis of the car is the ground

Close proximity wiring signal induction appears based off this formula, which is part of magnetic/EMF theory (This forumla applies only to expanding/contracting/moving magnetic fields, not static fields. As a result, pure, unchanging DC does not apply, only something with a changing current flow, like AC or DC that is fluctuating):

cos(angle of interesect)=Induction (as a function of original signal)

In a side by side run:
cosine(0 degrees) = Induction potential
(1) = 1

45 degree intersect:
cosine(45) = induction potential
(.5) = .5

in a 90 degree intersect:
cosine(90) = Induction potential
(0)= 0

Weeee... That was fun, wasn't it? I never liked trigonometry or related functions (sine, cosine, tangent). I guess my teacher was right, it DID come in handy...

That could be turned into a percentage I guess, and say you have a 100% chance of getting induced noise in a closed system (Even if it is not perceptible to our ears) if the wires run parallel to each other, and a 0% chance if they are 90 degrees to each other.

I think I am going to go pass out now.

-Phil