The PS301 is the ideal combination of analog/linear and digital circuitry. The supply section is linear with a toroidal transformer coupled with linear regulators to virtually eliminate stray-field radiation. The PS301 will play well with other sensitive audio and lighting gear with which it shares rack space. The performance of the power supply is extensively monitored by a microprocessor which detects heat, voltage and the status of both the input and output. Each of the three circuits is monitored independently and faults are reported to the front panel. A red LED indicates when there is a problem with each circuit by flashing. If the fault requires shutting down the circuit, the LED lights steadily. The circuit resets when the fault is removed without booting the power supply. The power supply provides power for up to 66 beltpacks connected to the circuits. Power is well regulated at 24 volts DC and will automatically adjust down during periods of line voltage brownout or high loading with speaker stations or other equipment. Short circuit protection and current limiting prevent component damage in the event of connection error or cable failure. The PS301 has a quiet built-in fan that turns on automatically when needed to cool the unit. Each circuit has a characteristic impedance of 200 ohms at audio frequencies, allowing many beltpacks to be connected together without significantly changing the circuit performance. The circuits may be linked in A+B or A+B+C configurations via a front panel switch. The termination networks are automatically removed and inserted during circuit linking to ensure a constant impedance for all circuits. The termination networks may also be manually removed by setting a switch on the rear panel, if desired. This may be useful when using an adjunct network, or if interfacing with a larger communications system. The PS301 has a program input which can be directed to any or all of the three circuits. Each circuit has an LED VU meter to report to the operator the level being sent to that circuit, and a control to regulate it. The PS301 will operate in either the 120VAC or 240VAC range. Selection and correct fusing are done on the rear panel. The power inlet is IEC and we supply power cords with the correct plug for most of the world’s electrical outlets.