I could be wrong, but according to highfidelity.pl review of BAT VK-P6SE:
The VK-P6SE is a balanced design, with a passive "floating" RIAA correction circuit, ie after the RCA input the "positive" signal is amplified in one branch of the gain, and the "negative", which normally is shorted to the ground, here is amplified in the other branch. The ground connection is made with a separate cable run from a tonearm.
Does it means even though the cartridge connected to the VK-6SE inputs via rca cable, it still worked as a balanced connection?