I recently acquired a THP HL-1K/A tube amp and I am looking for the amp-to-xcvr control cable with 3-pin male plug to mate with the 3-pin female socket on the back of the amp. According to the amp manual, this cable connects the STBY (i.e. send or TX gnd) and ALC lines to the xcvr. There is a diagram in the manual that describes the cable as having 3 wires, which makes sense as there are 3 holes in the socket. But, as for how the cable is terminated at the xcvr end, no information is given. I suspect there may have been 2, male RCA plugs; one each for the send and ALC lines, with the 3rd wire (which is amp chassis ground), split and attached to the ground side of each RCA plug. I doubt that it will be possible to find an original cable, but it should be easy enough to fabricate one if I can find the 3-pin male plug that mates with the socket on the amp. Any information on a source for this plug would be greatly appreciated. Reply here or direct to my email address on QRZ.com. Thanks! Mike, N1OKL