@stephens770 I have seen a modified SC unit to use XLR. Pretty expensive proposition though. Contact Hartmut at Bayer Soundworks in Germany.
He also has a modern take on the crossovers.
I still run the bass with Threshold 12e but the mid/high are now powered by Manley Snappers after i lost the VTL/Manley Ref 100/200.
Funny, I have a spare never used VTL/Manley Ref 100/200 but could not find another one to complete a set. Very expensive paperweight.