No Way! The Heath SB-220 and SB-221 had 2 each 3-500Z tubes. The SB-230 had a single 8873. Glen, K9STH Website: http://k9sth.com --- On Wed, 7/1/09, Charles Harpole <k4vud at hotmail.com> wrote: Heath SB-220/230 used TWO 3-500z.