I just pull the power out of the back of mine. It's a pain but it works well enough.
I've found to get a good sound of the Tube MP you have to crank the input gain to at LEAST 70%. Unfortunately, this is also where it starts to get noisy....but the noise is nothing compared to the signal it's pumping out. Also, it truely does sound best after about an hour or two of warming up.
I don't like the way it's geared though. I can't really overdrive it with an SM57. I typically have the input gain to 80% and the output gain to 60% (+20db). On the other hand, I can overdrive it with my Sansamp Bass DI box, but then the output is geared too high...in that I'll have my input set to 75% (sounds great) and then I have to set the output gain to about 15% !!! I'm probably nuts, but it sure seems to me like this thing sounds best when I'm able to crank both the input and output. Oh well.
Slackmaster 2000