Anyone tried running PS Audio P-300 with no fan ?

Go ahead! My PS 300 is feeding the Wadia 270 transport, the Wadia 27ix DAC, the AudioResearch SP14 and a Sony DAT-Recorder. No problem whatsoever. Display reading 80 watts.
It's HOT, yes, but I don't care. The Multiwave II upgrade has cooled things down a bit, though. Just make sure that the PS 300 can "breathe" top, bottom left and right and you'll be ok.- If still in doubts ask Paul McGowan (PS-Audio owner), he is very friendly and will answer all kinds of questions - a pro to all PS-Audio gear by the way.
Good lcuk!

As I suggested before: go ahead!
It's OK that a unit like a PowerPlant is running hot! Every Class A amp does, let alone tube gear. So I never understood the introduction of the fan at all, because if you intend to run high loads where cooling down might be a necessity, there is always the 500, the 600 and the 1000 PowerPlant. And sure Paul knows what he is doing which you can see taking a closer look to the housing which certainly IS a heatsink!