Externally mounted amplifi ers provide an additional 50 or 125 watts of addressable audio power when con nected to the ECC-50/100 Up to eight distributed amplifi ers can be connected to the ECC-50/100 for a total of 1100 watts of audio power Includes four built-in speaker circuits which are expand able to eight circuits with an optional ECC-CE4 module (A maximum of 24 audio circuits) Speaker output voltage is fi eld confi gurable on ECC-50DA for either 25 volts or 70.7 volts of operation Includes a built-in power supply and backup battery charger ECC-50BDA provides 50W of power with 50W as back-up. It can also provide 100W of power (100W of back-up power requires ECC-50WBU)