Richard,

DR-9 just sold on ebay for $432.50. It is very similar to the way you've described your DR-11. Has the 3 piece back. It is stamped on the back brace, so that would indicate 1980-1984. IIRC, you indicated yours was earlier than that, but it is still made in Japan.

Brought some pretty good money, I'd think. Whoever bought it got a very nice guitar, and whoever sold it got a very good price for it...