ok, so I hooked up and tested the switch. It works great. The amp turns on soft as soon as (ie right after) the tv powers up. Once the tv turns off, the amp powers down soft again (counted 7 seconds as advertised). Thanks @imhififan
With this device I can also add a fan if I need. The B&K St140 sounds good for TV, but I'm trying to do some streaming on this system so I would like to get a better amp. I could use my Eagle 2Cprime which sounds great with the Sttafs, but the face plate is 19" and won't fit through the door.
So now I have a few amps I'm on the lookout for . . .