Would it make sense and be safe to put power conditioner in front of PS Audio regenerator?

No. the PP rectifies the input AC and starts all over inverting it. anything you do upstream can only hurt. traditional power conditioners have a nasty habit of limiting current.

a dedicated line does almost nothing to improve the quality of the power--it ensures that you have adequate current. It also ensures you don’t have something else plugged into the circuit that causes noise. you can manage this yourself by figuring out what other outlets are on the same circuit and either moving things to other circuits or making sure noisey appliances are off or unplugged while you are listening.

Jerry

@jea48 Not saying I don't recommend a dedicated line if you can.  I have one, 10 awg.  

But the dirty power happens outside the home and you can't do anything about it with a dedicated line.   Not most of the dirty power, but 100% of it so long as you have nothing else on the circuit.

I discussed getting other loads off your audio power circuit.  

Jerry