Line level RCA cables are pretty much all the same (contrary to what the Best Buy sales guy will tell you). Weather you go 3' or 100', it shouldn't matter. Don't break the bank on sub a cable, or any other for that matter. Buy cheapest 50' foot cable with RCA ends you can find. Just ensure the RCA connections are in good shape.

Paul

paul

Axiom M80, VP180, Qs8, EP500
Epson 3020
Rotel RB-880
Denon AVR-990