Jtinn is correct - BAT's preamps on startup have a large current draw, and as a result the P300 shuts down in response to this current demand. There are a few posts on www.audioasylum.com relating to this issue (including posts by Mr. Khomenko, IIRC). The Hydra does not have this problem, nor should the Exact Power EP2000 or Sound Applications CF-X. However, I would hesitate to call the Hydra a "huge step up" from the P300.
HELP Anyone Using a PS 300 w/ a BAT Preamp?
Just bought a PS 300 to use w/ my CD player and preamp. However, the PS 300 shuts down whenever the preamp turns on! The preamp is a BAT VK5 SE, whihc goes thru a 30 second "warm up period" before turning on. During the warm up (display blinking) the power draw is 19o watts as measure by the PS 300..however..whent eh warm up period nears completion, the voltage goes past 300..and the PS Audio shuts down. Anyone else experienced this problem w/ a PS 300???!!!!