Hmm, this gives me an idea - if we came out with a time machine kit you guys could build it first, then order an amp kit, and then jump forward 4 weeks.
Ooh, and if you make a mistake in the build you could just go back before you did and correct the mistake before it happens (happened?).
I can't really think of many other practical uses for a time machine, but this might make it all worth it. I googled, and it has been done before with vacuum tubes...
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fvignette2.wikia.nocookie.net%2Fbttf%2Fimages%2F0%2F04%2FTimeControlTubesModel.jpg%2Frevision%2Flatest%3Fcb%3D20080802225029&hash=a4cb3b9a00831739670af1460e4fe6455403c11b)