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      06-06-2011, 11:58 PM   #48
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Quote:
Originally Posted by digitaldav View Post
From what I have read testing amp by using shorted rca or muting plugs, some call them, connected to the input of the amp can determin if noise is generated from the amp. I have done this and again there is no noise when mute plugs are connected to the input of amp. Even with the gain turn way up there is no noise when input is shorted.
Are ALL the RCA cables disconnected from the amp when you do this test?

Is there any chance that your RCA cables have the L and R shield common, or have any metal barrels touching each other or touching ground? ASre they coaxials rather than twisted-pair?

The (-) on the shield out of the BMW HU is NOT a common-ground signal like RCAs are supposed to carry. You want to make sure you don't have metal barrel RCAs touching each other or ground, and you don't want a coaxial, foil-shield RCA, you want a twisted-pair RCA.
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