In the old days, prior to common use of XLRs, balanced connections were executed by the use of barrier strips with screw terminals. To really do that right, the spade or ring lug used in such a connection should be crimped properly to the wire.
However the whole thing is solved rather easily if the source driving the balanced connection is low impedance and able to drive a 1000 to 2000 Ohm load. Quite simply, any issues with the connection are swamped by the current. That is how they did it in the old days again but the load impedance was actually 600 Ohms. Microphones often used a 150 Ohm input impedance at the microphone preamp.
If you are getting sonic differences as you describe its a good bet your source does not support the low impedance aspect of the balanced line system. You might see also if it supports AES48; if not, you'll find that the interconnect cables themselves have as much or more effect on the resulting 'sound'. Its sort of akin to placing too much weight in the rear of a car so the front wheels have little authority, or having a tiny rudder on a boat, allowing wind and waves to overpower it.