MOSFETs
https://en.wikipedia.org/wiki/MOSFET
Big ol' transistors that do a lot of the work in the amp.
So in other news, the craptastic health insurance I have has this program where you take a survey about your health/habits/etc and they give you anywhere from $50 to $200, then if you were less than perfect but improve they give you the balance.
http://www.fchp.org/en/members/healt...alth-plan.aspx
Seems like a trap. You sell data about your personal habits, then in a few years they jack the rates for some people maybe? Not sure what their game is but I'm not sure I want to do it, though I could use the cash.