[bummrush]

Got all cables , power plugs unhooked. All except power cord to amp and left  right interconnects to pre amp.  A very random ping sound will come out of either pre amp or CD player . For the life of me I just don't know what would cause this.  Could this ping sound travel through a interconnect and send to the pre? It's a fairly loud sound.

[avta]

I've occasionally noticed what might be called  "ping" sound as equipment heats up. I thought it might be from tubes or metal expansion. You might try turning on one piece of equipment at a time with no cables or connections to other pieces.

[Speedskater]

And then again, it might be interference.