[R-390] Filter pins

[Dan Merz]

Hi,  I'm trying to use a NIB 2 khz mechanical filter of 390a type as a
substitute for the single ended type Collins filter that went into a
nine pin socket in my Mackay tube radio.  I have a couple of questions.
Has anyone accomplished this or a similar adaption?  I know the input is
the upper end but I'm wondering whether the two pins on each end are
"equal" with respect to ground - can I put the input connections either
way on them? Similarly can I put the output connections either way on
the lower end?  There will probably be other problems,  like getting the
leads from the top to bottom to behave ok.  My first inclination was to
try to make it a plug-in unit with 9 pins but I'm starting to think
maybe I should just pull the socket out and mount the filter in the
hole,  much as it's mounted in a 390a,  and feed the top two leads thru
added holes in the chassis.  Any ideas?  thanks,  Dan.