What's the current draw per blade?
It's around 15 amps per blade. I'm not sure what happens when you only power one blade. The controller board is mounted to one of the blades, and probably powered from it; if that one is unpowered the entire rig is very likely down.
No I mean I use one 300w power supply for blade 1
One 300w power supply for blade 2 and controller
And the same for the second antminer
So 4 x 300w power supplies
Most 300w power supplies put out more than 15A
So, in theory, it's a valid setup
of the 300W, how much 12V? you need about 16-20A of 12V per blade if not overclocked, and 20-24A per blade if overclocked