Buzzing sound in my radio ? Need sound advise, Link added to a car audio DIY Education Options

[TC 914-8]

I was triing to clean up my center console the other day and moved my booster from inside the console to the outside, passenger side. once I did that I have a very loud and obnoxious buss in my raido. If I plug in and play my I Pod directly into the booster, no noise (IMG:style_emoticons/default/confused24.gif) . I have grounded the raido, booster, even went as far as grounding the sheilds of the RCA cables (and tried different cables) into the booster. That seemed to quiet it up a slight bit but still buzzes when the FM, CD is on.
I then went to raido Shack and picked up a noise supressor (inline capacitor) Still didn't help.
I am begining to think Ignition or Alternator? Every thing was fine till I moved the booster from inside to the outside. This happened once before but not as severe, I just moved a few wires around and it went away.
Any ideas??

Here is the link I found good for the DIY guy who knows enough to be dangerous.
http://www.bcae1.com/

[Mike Bellis]

Usually grounding the RCA's does more harm than good. You should only ground the radio side. But that can cause a ground loop and induce noise too.

I'm thinking you should move your booster (amp?) around and see if the noise level changes.

If you have an old walkman. You can remove the tape head and extend the wires. Press play, put the head phones on and wave the head around your equipment. the head will pick up the source of your noise. You will hear the engine/alternator noise when you get the head close to the source. once you pin it down, make minor adjustments to the mounting, grounding , wiring until you hear a difference. I have a walkman setup for this from when I managed a car audio shop years ago.

[windforfun]

Usually grounding the RCA's does more harm than good. You should only ground the radio side. But that can cause a ground loop and induce noise too.

I'm thinking you should move your booster (amp?) around and see if the noise level changes.

If you have an old walkman. You can remove the tape head and extend the wires. Press play, put the head phones on and wave the head around your equipment. the head will pick up the source of your noise. You will hear the engine/alternator noise when you get the head close to the source. once you pin it down, make minor adjustments to the mounting, grounding , wiring until you hear a difference. I have a walkman setup for this from when I managed a car audio shop years ago.

Excellent suggestion. I need one of these.

Don't you mean that ungrounding the RCA phono connectors (or going to a floating chassis) will eliminate ground loops. The shielding must have zero current flow.

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

[Mike Bellis]

Excellent suggestion. I need one of these.

Don't you mean that ungrounding the RCA phono connectors (or going to a floating chassis) will eliminate ground loops. The shielding must have zero current flow.

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

some drain wires are shunted to the shield. When this is the case, a ground loop can form on the signal ground. The cheap thin RS RCA cables have very little shielding. These do not protect from EMF noise.

I should ask what brand and how old is the radio? if the radio amplifier circuit board looses its ground, noise can happen as it uses the RCA shield as a ground path to the booster (amp). The RCA ground loop isolator can eliminate the noise at the cost of fidelity.

At this point I would first consider splitting up the amp and radio ground wires and screw them seporately. sand the paint down at the connection point and drive a new screw into the chassis. You may have too much ground potential going through your existing connection.

[windforfun]

Excellent suggestion. I need one of these.

Don't you mean that ungrounding the RCA phono connectors (or going to a floating chassis) will eliminate ground loops. The shielding must have zero current flow.

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

some drain wires are shunted to the shield. When this is the case, a ground loop can form on the signal ground. The cheap thin RS RCA cables have very little shielding. These do not protect from EMF noise.

I should ask what brand and how old is the radio? if the radio amplifier circuit board looses its ground, noise can happen as it uses the RCA shield as a ground path to the booster (amp). The RCA ground loop isolator can eliminate the noise at the cost of fidelity.

At this point I would first consider splitting up the amp and radio ground wires and screw them seporately. sand the paint down at the connection point and drive a new screw into the chassis. You may have too much ground potential going through your existing connection.

So the ground is floating? It is a car after all.

BTW, what's a drain wire?

[Mike Bellis]

So the ground is floating? It is a car after all.

BTW, what's a drain wire?

The RCA ground can be floating but generally it is bonded to ground at the head unit. The shield carries half of the audio sine wave, so there will be trace current flow. On most amplifiers the shield is floating and not connected to the chassis. In the cases when they are bonded, it is usually through a high resistance circuit. This helps to isolate the audio signal from the chassis ground. In many cases when the two component's RCA cables are at the samp electrical potential, this creates the ground loop and causes noise. An RCA ground loop isolator is simply an audio transformer that keeps the electrical ground seporated. Because the low voltage audio signal must drive the primary coil of the transformer, signal quality is effected. Noticeably on bass frequencies and somewhat on high frequencies. This will directly alter the audio signal on the secondary coil of the transformer.

A drain wire is the ground wire on a shielded cable. They are designed to absorb transient EMF and shunt it to ground. Thus mitigating signal interference.