The Kenwood TS-520S is negative keying (Has tubes) the TS-430S is positive (transistors finals). The PK-232 has output for both on the back and it will handle the voltage of the TS-520S without any problem. Joe K0BX T.L.Tallman wrote: > is the keying of the 520s and 430 postive tip or negitive i would like to hook up my pk-232 mutimode thxs terry N0WJH