ust a comment on PS Audio I had. I actually sold my PS Audio PPP to buy the PS Audio P600 when I found out the P600 (only with added upgrade curcuit board) can change the A/C output to any frequency between 60 to 120hz. This is a rare ability, but one I discovered reading old Stereophile articles.. and worth the search for one. The P600 must already have the optional upgrade beard insstalled, as no more new ones are available from PS audio.
I love running mine at 110hz for my digital stuff. The increased frequency of the A/C voltage give a smoother sound... (though not good with digital type power supplies)
So only my Behringer DEQ2496 is not happy with the PS Audio at 110hz output (of mmy digital components).