Balanced vs. Unbalanced - What does it mean?

I have a McIntosh MC402, I am using the Unbalanced inputs - my dealer hooked it up for me. Everything sounds fine but I am wondering about the Balanced input. When do they get used? Does it sound different? Which is best?

Try 'em out and see for yourself. of course, your source or preamp has to be likewise outfitted with xlr outputs.

Usually if truly balanced the back drop will be darker or quieter... less noise. There might also be a touch cleaner sound presented given the balanced approach. other's will say this with more technical insight.

If you feel such a change from SE to XLR will provide you night and day diffs, I doubt that notion will prevail. Albeit, it is likely going to be a noticeable one... again, if truly balanced.
I had an Ayre amp and preamp which I used for years with RCA's because I didn't think the more expensive balanced cables would make a significant difference. Then I got the audiophile bug and tried balanced cables. There was an obvious improvement, well worth the extra expense.
We need a better technical explanation. I asked and was given two different answers. One it just means that the signal is always kept equal between the two channels. As if centered if there was balance pot that made sure it was centered. with a dumb look-- like you know --balanced.
I thought it would always be balanced if you have no control. AS in the usual setting for a any option which is no longer worth making the signal path longer for. If you are thinking like a true audiophile.
As if the balance knob is alway dead center. Which what you got when the preamps and integrateds had a balance knobe and a defeat button/switch to employ. The balance is defaulted to precisely equal for both channels.
The other answer was that the signal is always kept grounded in essence with hand waving.... you know?? I don't! The expense and lack of xlr inputs on the first couple of amps has kept me using RCAs that are SE I guess. Although they could be SPDIF lurking in RCA clothes for all I know.
Where are the technophiles, bring in the technophiles.
The techies can tell you what it is but cant tell you how it sounds.As usual synergy rules and that is to be found in the arena,not on paper or cyberspace,YMMV,cheers,Bob