Popping from light switches and refrigerator

Help please! My amp just quit working and no one knows why! Two weeks ago the output light on my pre-amp burned out and there was no sound through the system even though the pre-amp tested fine when I sent it in for repair!

I just moved into a patio home (on a concrete slab) three weeks ago. WHEN the stereo actually works, the CD transport misreads and there's a pop out of the speakers when a light switch is flipped, the refrigerator door is opened or the refigerator cycles on.

I've had an electrical engineer look at it and said it was just line noise. I had an electrian come out last Friday and he couldn't find a reason. The three lines coming into the house were all tight and the breakers were all tight.

The light switches and refrigerator are on four different breakers. The electrician suggested running a dedicated line. The electrical engineer said that that wouldn't help since the switching noise seems to be bleeding through four different circuits now.

This happened (before the amp quit working) with both a tube pre-amp and solid state pre-amp. It happened with both a $2500.00 power conditioner and a UPS unit from my computer.

I lifted the ground on the transport, dac and pre-amp and the popping seemed to stop (for that day). The next day the power amp quit working altogether. I don't know what to do!

Chuck