xlr vs. rca- volume gain

All things being the same does the volume level diminsh with balanced as compared to unbalanced interconnects between cd player and integrated amp? I have Simaudio I-7 integrated and Supernova cd player. I have pair of Signal Cable Silver Resolution interconnects both balanced and unbalanced. When using the unbalanced the volume is louder than when using balanced at a given volume setting on the integrated. I am confident it is neither of the components. The same thing was true when using a different cd player with balanced and unbalanced connections.
There are no exact standards about the signal levels between components . . . the "IHF 250mV" level and the "Red book 0dBFS=2V" levels are specified, but only very loosely conformed to by manufacturers.

This is true of how unbalanced vs. balanced connections are handeled as well. In professional equipment, it seems that many manufacturers try to keep the same amount of gain for both types of connections - this is a hold-over from the days when transformer-coupling was ubiquitous, and there would be no reason why the gain would be different. In consumer and semi-professional equipment, it seems that many balanced inputs have 6dB lower gain than their unbalanced counterparts, in anticipation of the 6dB higher output that is common for "transformerless" active balanced output designs.