I have a BAT VK-50SE and it is definitely too much of a load for a P300. I have purchased a P600 and I can tell you that in my system, it made a huge difference, and the only thing plugged into it is the BAT. I have a P300 that all the digital stuff is plugged into. My guess is that you are overloading the P300 with all you have plugged into it - not to the point of tripping, but to the point of "choking" it. I would receommed the BAT directly into the wall or, into a second P300 to let the system "breathe" better.
PS Audio PP300 works great, but......
Seasons greetings. I hooked up my brand new PP300 last night. If I listen critically and technically, I can clearly state that it does EVERYTHING they say it does. Much blacker background, Much tighter bass, Much greater detail and instrument space. However, even though all of these things are done better than I ever imagined, I find the music to be less involving. Has anybody else had this experience? Will it get better with break-in? I don't want to give up all of these benefits, but I want my musicality back. FYI: Sonic Frontiers T3/P3, BAT VK5i, BAT VK500, Dynaudio Confidence 5.