ground loop breaker

[biff584]

I built a P3A amp and was having problems with ground loops, so between the amp's signal and power grounds and the earth ground I place a loop breaker consisting of two diodes in parallel in opposite directions and a 10 ohm resistor. This greatly reduced the ground loop, but I can still hear it- are there any other adaptions I can make to further reduce the effects? I was thinking about upping the size of the resistor, removing the resistor, or maybe even trying to add a simple RC low-pass filter designed to reject frequencies at and above 60Hz between the signal and earth grounds.

Thanks alot.

Brian.

 

[trwh]

Hi

You could try increasing the value of the resistor - although I wouldn't leave it out altogether. In one design I saw a 100 ohm part used; as long as you keep the diodes any value is safe to try. Many designs also use a 100nF mains rated capacitor in parallel with the other components to bypass the resistor at high frequencies.

Hope this helps,
Tim.

 

[biff584]

Thanks, I'll give that a shot and try a 100 ohm resistor instead and see if it help much.

Brian.

 

[ukram]

Try reading Jensen application notes.

http://www.jensen-transformers.com/apps_wp.html

You should show us a picture with the ground connections of your whole system...