The Minimalist Superhet Radio project.

[Geordie McBoyne]

So much so that contributor Synchrodyne mentioned in an earlier post that because the noise performance of the ECH81 is so good the requirement of an RF amplifier can be obviated.    The ECH81 has the best conversion conductance of all the known frequency changer valves, better than 0.7mA/V.
From the Valve Museum:    
http://www.r-type.org/exhib/aaa0036.htm

Geordie McBoyne.