Furutech AC Receptacles

Many find that power amps sound best plugged directly into the wall. In particular a regenerator such as your PS Audio is a pretty wasteful way to power a class A amp and may restrict dynamics. 

Personally i I get good results with the Synergistic PowerCell 12UEF but to start with go direct to the wall and on a circuit that's not shared with any of your other components 

@wylmars but surely you read the next page of the manual that states there's no problem using alternative power cords

to quote p7

Caution should be taken before using custom after- market power cords: they must be at least 12-gauge and have a standard grounding plug properly installed. These power cords are to be used with caution, at the sole risk of the owner.

Don’t worry. I and probably most other ARC owner on this forum have been using after market power cables for years and have no issues with warranty work. In fact most dealers demo these amps with after market cables. The dealer I bought from, Optimal Enchantment, always demos with AudioQuest for example

The cautionary language is just to avoid issues if you for example slap a 20A IEC on a 2 conductor lamp cord and then burn your house down!

and btw the warning on page 6 of the manual was more related to the second half of the sentence which you did not quote - the bit warning to always use a dedicated outlet and not a convenience or extension

@wylmars Firstly I trust by now you've learned to tale any advice you get on the internet with a pinch of salt 😏 and as @cleeds suggests you should try it for yourself, both into the P10 and into the wall.

My cavil with PS Audio regenerators is that basically they are power amps outputting clean 110V -- agreed the newer ones such as your P10 are efficient (rated 85% at peak continuous load of 1200W) but they are throwing away 15% or more energy than you need. Early ones like the original P300 (I at one point owned three) were <50% efficient and ran hot as hell.

However while the P10 is rated with enough power to drive your Ref 75 (peak load 500W) the consensus (and again you have to listen and see if you agree) is that Power amps in particular prefer a non current limited (i.e. more passive than active) power conditioning regimen, and in many cases sound best run straight from the wall. Sources (your Ref 5SE and Accuphase kit) will benefit most from the clean power the P10 provides

So to conclude -- try it all ways and see what sounds best to you -- that's all that matters