Power strip for sequenced preamp/amp turn on and turn off?

I have both a tube preamp and power amp and religiously follow the mantra of "preamp on first, the amp on... then amp off and preamp off."  Well, yesterday, I got tripped with and reversed the sequence and swear that I have never heard 3-4 seconds of distortion ever so awful out of my speakers until the electronics settled down.  I don't think I blew a driver, but it could have had a good effect on the speakers.  

I am lead to believe that their are "power strips" or devices that you can connect one's amp and preamp to that will automatically sequence the amp and preamp turn-on and turn-off.   Can anyone head me in the right direct for such a device?