Will line conditioner do anything for the other receptacle in a duplex?


Would it provide the same purported benefit as the Venom Defender, Furutech NCF Clear Line or Magnetic Wave Guide products?
tcutter
If that is the case then at some point you might want to try some things that actually work. Because I have them, and there is no "testing" you plug em in and hear the improvement immediately.
It should, as the these pieces are designed to take a "dirty" incoming signal, and send out a "clean" one.  The "clean" signal it sends out goes to your gear *AND* back to the outlet/duplex, hence a "clean" duplex (theoretically a whole circuit).  The effect will *not* be as strong on the duplex (or circuit), but you should get a little bump.Cheers!
The purpose of the module type power conditioner is to clean the AC line from the receptacle to the service panel. That includes both duplexes which are connected.
 Often, multiple modules are used in separate duplexes to reduce noise on other lines which will meet at the panel. This will have an cumulative effect. 

A line power conditioner is plugged into a receptacle, it's function is to reduce noise from the mains to all components which are plugged into this unit. It is only cleaning the AC for your audio system, it does not send a cleaned return signal to the panel.

There are so many different power conditioners, each with it's own unique design.