Typical ricebox should run 25-30 Watts (1/4 to 1/3 of the input power) in order to sound good and remain linear. (assumes 100 Watt radio). The sound good part depends on the microphone, rig audio capability and last but not least, the operators voice characteristics. No amount of processing will fix a rough sounding voice. (IMHOP). 73, Charlie, K0NG