2 of these circuits:
http://v3.espacenet.com/origdoc?CY=gb&LG=en&F=4&IDX=US2431569&DB=EPODOC&QPN=US2431569
make a perfect wobble/tremolo-free up/down pure Tube-Chorus(TM), when the SP-generator is being modulated by a LFO.
>only few adaptions/mods needed additionally<
(back in the days, they called the guitar-signal: "intelligence" :wink: )