XLR to RCA conversion

I have learned that my Manley monoblocks perform better using a single-ended input, rather than the balanced cable I am using.

If I were to buy the Cardas converters that would enable me to convert the XLR to an RCA at the amp end, would I (1) have to do the same at the Audio Aero Capitole output end or could I just convert the input or amp end of the connection?

I have to use my 40 foot balanced interconnects and want to go single-ended at the amps and HOPEFULLY still get the benefit of a balanced cable and the noise rejection it provides.

Thanks in advance for your help.