Tributaries - CABLE-6D - Bulk Video Cable (100m) The Series 6 begin with silver-plated ultra-pure highly conductive oxygen-free copper (HC-OFC) developed specifically for digital audio applications. To maintain a consistent 75-Ohm impedance, the coaxial Series 6 cable’s 20AWG silver-plated center conductor is surrounded by three perfectly concentric layers of dielectric which consist of a skin, foamed PE and a final skin. Heavy triple shielding block noise from entering the signal path.