"I need the approximate input impedance for a pair of 572-B's?? I am working on the input matching on an SB-200 to six meters. Abt 60ohms??" More on the order of 200-ohms. Roy K6XK -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative requests: amps-REQUEST@contesting.com Problems: owner-amps@contesting.com Search: http://www.contesting.com/km9p/search.htm