The COS series transformer units, allows 70V/100V installation connectivity beyond reproach. It has within it a 2 or 4 separate torodial line matching transformers housed within a 19” rack mount chassis with Phoenix type connectors for rigidity and endurance. Separate line input for all channels assures flexibility. A low cut filter which cuts off frequency below 80Hz, ensures safety for the 70V/100V transformers and also installation loudspeakers. Amplifiers from the RX, DJ, EX and ST series can be made into top notch installation amplifiers using the COS units.