Tributaries - 6BA - Series 6 Bi-Amp Speaker Cables (Pair) Tributaries 6BA is a high-performance Bi-Amp Speaker cable made by hand. The 6BA is designed with heavy 14AWG High Conductivity Oxygen-Free (HC-OFC) copper conductors that are terminated with Series 6 spring clip banana plug and/or spade lug connectors. The conductors have a unique individually insulated dual-gauge configuration for superior sound clarity. The 6BA is terminated with red & black Series 6 spring clip banana plug and/or spade lug connectors. The wires are secured by dual screw terminals in the connectors.