RCA Interconnect screen side

Usually RCA IC has screen connected at SOURCE end. I am fine with that. 
How about this specific situation:

I would like to connect Step Up Transformer (signal source), passive and not grounded unit with active phono preamplifier - the only one grounded unit in my system. 

In this case should I connect screen at the signal source side or rather at the side of grounded unit (phono preamplifier)?

thanks.