I recently replaced my refrigerator with a brand new LG model LTCS20220W. The fridge is silent, but when it is running, my guitar amplifier is picking up a 4,500Hz signal which is driving me crazy. I used a spectrum analyzer on the output from my amp to determine the frequency of the noise.
The noise seems to be coming over the power line, since it's still present even when nothing is plugged in to the amp, and the input volume controls don't affect the noise volume.
I've looked on line for power EMI filters, but they all seem to start down at the 150KHz level.
Does anyone have an idea on how to filter this noise out?