At what distance are balanced XLR cables needed?

I have a McIntosh C2300 preamp feeding a McIntosh MC402. They are 16 feet apart. I have used both Balanced XLR connections and RCA single ended connections. The balanced has sounded better every time. By the way the RCA Single ended cables were supposed to be more highly regarded and definitely way more expensive.

So, to answer your question, I found 16 feet the distance in my system.

I would suggest using the very best cable and connectors available, and if that means using XLR's, by all means use them.

Atmasphere, unfortunately I don't like gain at 60ohm position. Not many solid state amps have 60ohm output impedance while the most of them cannot drive 600ohm. The reason for that are op-amps used. Only few like LM4562 or OPA1611/12 are designed specifically for that. In addition most of preamps have output capacitor not designed for 600ohm load. I used to solder resistors left and right when I was young. Now I know better and do always whatever is "standard".

Kijanki, you and I are on the same page in that regard. It does you no good to drive 600 ohms if the circuit doing it sounds worse!