Heathkit was created in 1926.

This is a Stabistor - IG1271 - STB620

Lots of Heathkit part cross-references at http://www.tech-systems-labs.com/heathkitparts.htm; Google is your friend, try [heathkit parts cross-reference] for more...

For sound

My father built some of the early Heathkits. He made me a CR1 crystal radio as well. That would have been in the mid 1960's.

The Heath Company was purchsed by Howard Anthony in 1935 after his founder Edward Heath died in a plane crash. The first "kit" was a 5" Osciloscope to be built from World War II suprlus components. The kit was sold for $39.50 in 1947.