Preamp design approach - Power Supply location

I also own one of each design...and to be honest...the power supply seems to have marginal effect in my system...more relative is the features...or lack of them...pertaining to the preamps...

I think that Herman is correct, if you consider shielding as part of the power supply. Most design decisions involve compromise; I expect that is true on this issue as well. Certainly more cost to go to a 2 box solution. Those $ could be used to provide a bigger, better filtered and shielded supply in a one box unit. There are excellent examples of each, for sure.

I have experience in my system with both internal (cj 16LS, ARC Ref 2, Hovland HP-100, Lamm LL2) and external power supply pre-amps (A.I. Modulus 3A, Cary SLP-98P, and First Sound 4.0 w Paramount Plus upgrade).

While it is difficult to say what each pre-amp would sound like with the opposite power supply approach (don't have access to their prototypes--if they ever existed), I come down on the side of external P.S's.

I don't care for the extra chassis and connecting cord, etc. hanging around, but I am more willing to accommodate them than not.

dedicated external power supply is optimal all things being equal