The Minimalist Superhet Radio project.

[Geordie McBoyne]

I have decided the best frequency changer valve for this project is the 7S7, a triode heptode. This valve has a suppressor grid which means it shouldn't have RF tetrode characteristics, has a very good rA figure of 1.25Mohms. gc not bad either @ 0.525mA/V

The 7S7: http://www.radiomuseum.org/tubes/tube_7s7.html

Geordie McBoyne.