What are "true" balanced connectors

sleepwalker is correct.
A "true balanced input" means the + and minus of the input are differential, and not referenced to ground.

A "true balanced" amp means that both outputs are driven. Most amps only drive the red output.

The Parasound A21 as well as several of the Yamaha P2x00 amps from way back are examples of amps with XLR inputs, but they are not balanced.

Each signal is actually referrenced to ground, but the differential receiver only uses the two signal bearing wires to convert the differential signal back to single ended for further handling. 

Each signal is actually referrenced to ground,

Not universally true.

Best,
E

@luynes 
You wanted the right answer and I told you.
That Ralph is a designer and not an armchair EE, isn't the issue.
Now you have conflicting answers, and not the definitive one,
I guess you'll never know for sure. Good Luck
B

Thank you Erik!

YOU gave me exactly the specific answer I needed

Thank you Sleepwalker.

You gave me an answer to the broader question regarding what a balanced connection is. That your explanation may not correlate 100% with Erik's is irrelevant to me (beyond my pay grade!) ;-)

No Bob, you did not give me anything close to the "right answer" - Read my question(s) - then read your original reply -  then tell me if you still think you gave me the "right answer." I do not have conflicting answers. I now know EXACTLY what I needed to know about the Odyssey amp I was considering to buy...

I wish members would not use this very useful resource as a platform for "sales pitches"...