directional cables?

Thanks for the responses.

What if my pre amp (or TT or phono pre) has no ground pin on the power cord, just the power amp? What orientation now for the shielded IC's?

What if my pre amp (or TT or phono pre) has no ground pin on the power cord, just the power amp?

Consider yourself lucky. Provided of course that the chassis meet Class II specs and don't actually require the safety ground. The safety ground is the biggest source of ground loop and other noise.

What orientation now for the shielded IC's?

Same as you would otherwise.

The safety ground isn't a ground in the traditional sense. It's just connected to neutral back and the service panel and serves as a path for fault currents should there be a failure in the AC mains in the equipment which might otherwise cause the chassis to go hot and create a shock hazard.

It doesn't serve any purpose with regard to component grounding.

Even if your piece of equipment is floating there is still return - most likely capacitive. Cell phone is getting this return thru your body (just a few pF). Radio signals are in fact induced in in the cable (since shield most likely does nothing to stop it) but because of skin effect they travel on the outside of the cable - shield (field inside cancels). As long as this shield is related to system ground shield will protect against electromagnetic and capacitive pick-up.

Radio signals are in fact induced in in the cable (since shield most likely does nothing to stop it) but because of skin effect they travel on the outside of the cable - shield (field inside cancels).

Shielding basically works by two means; reflection loss and absorption loss. Reflection loss is due to the mismatch in the impedance of the shield and the interfering wave impedance. The interfering wave essentially bounces off the shield. Absorption loss is due to eddy currents induced in the shield.

Reflection loss is the primary mechanism when the interfering wave is largely E-field (electric field). Absorption loss is the primary mechanism when the interfering wave is largely H-field (magnetic field).