He had a patent for FET's twelve years before the bipolar (so well named
) transistor. His wife, whom he lost to Stalinist travel restrictions, was also brilliant.
http://en.wikipedia.org/wiki/Oskar_Heil
Off topic, I found this paper in a link. It explains, for the technically minded, what is so great about JFET's like those used by Nelson Pass in his best amps.
http://www.tkhifi.com/div/Erno_Borbe..._articel_1.pdf
"This description implies the primary difference between a bipolar transistor and a JFET: the pn junction in a JFET is reverse-biased, so the gate current is zero, whereas the base of a bipolar transistor is forward-biased, and the base conducts a base current. The JFET is therefore an inherently high-input impedance device, and the bipolar transistor is comparatively low-impedance."
Real word translation, the bipolar transistor is a current, not voltage, amplifier but serves better as a switch than as an amp. Amplifier use leads to thermal runaway, necessitating other circuits to prevent it or protect against the consequences.
Is this new Heil driver an update of the 1970's design or a reissue?
Clark