It is a hybrid. Three tubes and the rest transistors. One driver tube
(12by7) and two outputs.

There is a ton of information he
http://www.foxtango.org/ft101/foxtangoft101.htm

A friend in high school had one. I had an SB102 at the time. Maybe it was
a previous model, but my recollection isn't to great and I thought there
were more tubes. Thanks for the link. SB102 was a hybrid too, but only
because the calibrator and VFO had fets. there like 20 tubes to keep things
warm. I later had a TS830s with the 3 tubes. The hybrid radios with the 3
tubes were the very best of both worlds.