On Sat,8/15/2015 7:09 PM, Michael Eberle wrote: > At one time I had the KPA500, a tube amp, and a 2M amp for the > internal transverter all connected. For as long as I've had my KPA500, I've had both it and a TenTec Titan 425 connected to the K3's amp key line. The Titan key input is the base of a transistor. 73, JimK9YC