An optional second audio amplifier can be plugged into connectors J10 & J11 located in the upper right of the main con- trol board in the ECC-50/100. This amplifier also provides 50 watts of power at 25 VRMS or 70 VRMS, depending on the model, and can therefore be used to expand system power to 100 watts (providing dual 50 watt speaker circuits) or it can be used as a backup amplifier. The output is power-limited and speaker circuit connections to it are provided on the main control board and optional speaker circuit expander module. The circuit can be wired for Style Y (Class B) or Style Z (Class A) operation. For more information, including application examples, refer to the ECC-50/100 Manual P/N LS10001-000FL-E.