Ground loops are eliminated by eliminating the... Loop - this is why you connect the cold and ground lines of unbalanced connections using XLRs OR RCAs and 3 wire cable ONLY at the source.
That doesn't e;eliminate the loop, it just makes the loop much larger. You will still have Common Impedance Coupling Noise. But the current might flow thru the AC power system and your audio circuits commons.
For single-ended, unbalanced RCA interconnects, the best plan is to use a coax with a heavy braided shield.