Phono input cap to preamp

Currently reworking a Hafler DH-101. The question is regarding the input capacitor for the phono stage from the cartridge/turntable. If the phono cartridge only outputs an a.c. Signal, is a capacitor needed in that location? Is the capacitor there to prevent backfeed to the cartridge in case of failure? Currently there is an Elna 10uf 16v BP cap at c2. Seems as though one would not be needed but the interweb appears to be short of answers on this topic. Perhaps M.C. could drop a Truthbomb on this topic.