Steven Swift wrote:

A while back there was a 12v tube thread.

I saw this:

http://www.thamesandkosmos.com/products/ra/ra2.html

advertized in September Scientific American. The ad (on the
builditplayit.com site) says it uses a "double triode" and
requires 8-AA batteries (nominally 12V).

I wonder if it is a 12V tube kit. Perhaps a 12AE7 or similar.

Anyone know?

Can't speak for the kit but I know some guys have successfully used a
plain old 12AT/AU/AX7 at 12 volts with acceptable results.

-Bill