Benefit of shielded ac wire? Any downside?


For preamp and amp.
ptss
I recently moved to a new house. I have wired my system from the breaker panel with starquad 12 awg solid core wire direct to my distribution block. And a 10 awg , counter rotating, earth wire. Starquad has the advantage that it is a selfshielding type of geometry combined with lower inductance due to the double run.  I only use shielding on low level cabling and some digital equipment. Shielding gives blacker backgrounds, more details, but can kill the boogie factor and leads to compressing transients IMO. 
In Australia 240vac I believe it can’t be approved because it’s considered illegal and dangerous, and you wouldn’t be covered by insurance house or personal should the mains short to the shield, which would be attached to the case of your equipment also so it will become live as well.

Cheers George
tantejuut
... I have wired my system from the breaker panel with starquad 12 awg solid core wire direct to my distribution block. And a 10 awg , counter rotating, earth wire ...
Was this wire rated for the purpose and for in-wall use?
THe benefits:
Better rejection of EMI/RFI signals, like from routers, switches etc.
Negatives:
None really, though some claim the sound is duller.  I say it's because you are hearing less noise.
@cleeds . It is standard wire. I just braided it myself. It is a double run, normal wire for in wall use twisted in starquad. Pitch twist about 4 inch. It took a while for 15m. A good foundation for my system. Direct connection to my star wired distribution block, skipping wall outlets & power connectors.