...high-biased, 54 years ago:
blocks 352 & 353 in fig.13 (http://patentimages.storage.googleapis.com/pages/US3176262-7.png)
of
US-pat.#3176262 (http://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=3176262A&KC=A&FT=D&ND=3&date=19650330&DB=EPODOC&locale=en_EP)
provided with transformer-coupling...
who said it ain`t space-age technique?