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

"I could also experiment more with power cords from the wall but this Purist works well,"

Unnecessary audionervosa.

I use a PPP. It's 18 years old. PS Audio refreshed it in 2020, and good for another  10 years. They no longer support it.

The output display ISN'T 100% accurate depending on the calibration of the output/ display. There's  an adjustment pot underneath  the unit to fine tune it, which is done at the factory to display 120V.

With a Google  search and  a MM it can be done, if you're  a tinkerer. If you don't have experience with live circuit boards, best to just leave it be.

"Do you think that newer PS Audio P5 would be significantly better ?"

P5 is 2 generations old. Long discontinued. A newer PP isn't  going to magically transform  your system. If anything the psychological  "new box" will be in play for a hot minute. Naturally, just my take on using a PP.

I am not going to replace the Premier for as long as it works properly. Yes, I heard it is no longer serviced by PS Audio.

I wouldn't exactly expect dramatic improvement from the newer regenerators, significant improvents perhaps.

But the wall current is not going to improve, I guess, anyway.

@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

But the dirty power happens outside the home

Actually not. The majority of it happens within 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.

If you mean a convenience outlet branch circuit. Unplugging everything from the wall outlets except the audio system does nothing if the in and out wiring connections are not solidly connected connections. It’s possible there might be 8, 10, 12, or more wall duplex receptacles on the branch circuit wiring. The OP’s audio system might be on the closest outlet to the electrical panel or the farthest one.

Like I said in an earlier post a poor wiring connection can/will add noise, harmonics, into the circuit wiring that will transfer to the audio equipment.

Three things needed for a good electrical connection.

Clean connection.

Surface area.

Contact pressure.

I have no idea what wiring method was used to makeup the connections. The worst, imo, would be cheapo residential grade stab in the back duplex outlets. Junk! (Not to be confused with a duplex receptacle that uses a terminal plate that is tightened down on the wire by the 10/32 side terminal screw. The stab in the back duplex outlets are notorious for making poor, bad, in and out connections. Every one of them adds noise. Don’t forget there is a hot and neutral conductor. Four connections per outlet.

Then, it’s not unusual to have ceiling lights on the same convenience outlet branch circuit. Maybe they are can lights. Lamps are screw in LED. Add all them noisy drivers to the branch circuit.

Example: Stab in the back wire connection.

.

I wonder if audiophile grade outlet would help. No idea about wiring quality.