As someone who is a fan of both Thomas Pynchon and Buckaroo Banzai (who have never been photographed together by the way – think about it), I of course am familiar with the Yoyodyne family of companies.
I took the time to look up Yoyodyne on wikipedia and discovered several interesting things. For instance, it was frequently referenced on the John Larroquette show, which apparently made a number of cryptic Thomas Pynchon references that only wikipedia updaters have ever noticed or cared about.
But Yoyodyne Industries is now primarily working with making "Brane Power" amulets like this one called "El Brujo" (Spanish for "the witchcraft" or "the warlock").
If you look carefully, it does appear to have what looks like a crystal radio circuit, complete with zenier diode. I don’t recall much about crystal radios dampening beta waves back when they were in more frequent use, but we can assume that people were just more brane-intensive back then anyways.
I would buy one myself, but I think that $125 plus shipping is too much to pay to find out that my brane-waves are FM not AM.