Acoustic Research D240 RCA Jumpers

I just bought an Acoustic Research D240. It has standard RCA inputs, inverted RCA inputs and balanced inputs. On the back it states that if using the RCA inputs, that jumpers need to be put in the inverted RCA inputs. Without the jumpers the output from the amp was low compared to my B&K ST140, with the jumpers it was the same. The question is, where does one get good RCA jumpers. I assume some or all of the signal is running through this connection, so I'd like to get some gold connectors. What I fashioned was just some el cheapo metal RCA plugs that I soldered the tip to the ground. Haven't seen anything on the net....

Please keep in mind, this is not a two sided jumper cable, it's simply a RCA cable with the tip and ground connected.

My other question is... I expected the output of this amp to be louder than the B&K ST140, It's not. It's a better amp than the B&K ST140, but not louder.... The B&K ST140 is the second (louder) version of the amp (for those who know the different) Unless I'm mistaken, the B&K ST140 is 70 per side and the D240 120 per side. I'm using it in a production studio, it's been fed directly from the mixer, going into Martin Logan Aerius (original version) Any thoughts?