Then there are those who think nothing less than a glowing bottle will satisfy
tube aficionados. Perhaps that is true, but it isn't going to keep me from trying.
There are two things we want out of a solid state device for this purpose. First,
we want a “square law” input characteristic like that of tubes. Fortunately, Fets
do that already – the current through the Fet is a good square law function of the
Gate to Source voltage.