Vhiner -- Well, with all of that good protection and filtering, most likely one of the possibilities I was envisioning, that you have a damaged line bypass capacitor in one of the components, can be ruled out. That was why I asked about surge protection, and also about the age of the equipment.
However, the fact that everything is separately filtered, and the power amp is on a separate dedicated line, increases the likelihood of noise voltages developing between the chassis and circuit grounds of the different components. The degree to which that might happen would depend on the shield resistance of the interconnect cables, which connect the component chassis together. That is why I asked about the possibility of a damaged interconnect. I'm envisioning that the rfi (radio frequency interference) generated by a static discharge could induce noise into any susceptible point in the system, which would then get amplified by everything downstream, causing the pops you hear. A phono input would be a likely suspect, because of the high gain factor that is applied to it.
So besides continuing the interconnect experiments you are already doing, I would suggest:
-- Putting shorting plugs on any unused phono inputs, and/or disconnecting any used phono inputs and putting shorting plugs in place of the cables from the turntable.
-- Disconnect all source components from the preamp, and see if you still get the symptoms when the preamp or power amp is touched.
-- Disconnect the preamp from the power amp, and see if you still get the symptoms when the power amp is touched.
-- As an experiment (to help in diagnosing the problem) plug the entire system into the Guardian, assuming it has enough current capability, and see if you still get the symptoms.
Hope that helps,
-- Al
