Al Kossow wrote:
    The earliest
I have seen so far is a
 Sherwood FM tuner ca. 1977 that uses an RCA 1802 (e.g.
 
http://atlanta.craigslist.org/ele/927622156.html). 
 Bit of trivia. That tuner was designed and built in Milwaukee by a
 company that a friend of mine worked for. At the time, several of
 his friends built units up from leftovers from the production run. 
 
I should have made a better deal with my friend: fix one, keep one.
Apparently they are rather valuable now.
John Foust wrote:
  Patent says Grafton (northern suburb).  PDF manual,
including block diagram:
 
http://www.fmtunerinfo.com/Sherwood.pdf 
Interesting to see, although it was 11 years ago I worked on them.
I RE'd the schematic for half of it if needed. It was interesting to see the
1802 with all it's support in there when I first opened them up.