unbalanced to balanced

[Douglas Blake]

I can't believe how many threads are on this topic and how they continue to include misinformation all the time.

You are technically correct ... but in the common parlance, needed to communicate here, "Balanced Audio" means two out of phase signals.

 

[MarcelvdG]

This circuit can do the conversion in either direction. If the behaviour during clipping matters, R7 has to be increased or R8 decreased by a few percent to ensure that the feedback pair has slightly more tail current than the input pair.

 

[leadbelly]

You are technically correct ... but in the common parlance, needed to communicate here, "Balanced Audio" means two out of phase signals.

No, it does not.

 

[Galu]

Maybe it was one of the many diagrams on this page. It's been around forever (at least in net.time) and has just about every passive connection.
Sound System Interconnection

Just for the record, RCA to TRS is shown in diagram 18.

P.S. Ignore my post #9.

 

[Mark Tillotson]

A balanced cable carries 2 identical signals out of phase. This is often the exact same signal as on an RCA cable but with only one phase present.

So... with TRS and RCA connectors...

Balanced output to RCA input
Sleeve ---> RCA Shield
Ring ---> not connected
Tip ----> RCA Center

RCA out to Balanced input
RCA Shield ---> Sleeve
RCA Shield ---> Ring
RCA Center ---> Tip

These are not ideal connections --it is always best to connect like to like-- but in a crush they do work.

More precisely you describe a balanced differential signal, a balanced _cable_ has matching impedance on the two wires (symmetry), and is not always used to carry a balanced signal, just a differential one. A balanced cable rejects common-mode interference whether the signal is balanced or not, but especially well if it drives balanced input impedances and the signal is balanced too.

 

[Douglas Blake]

More precisely you describe a balanced differential ...

As I said... in "common parlance"... in it's most formal form of course, you are correct. And, yes, I knew that.

 

[leadbelly]

More precisely you describe a balanced differential signal, a balanced _cable_ has matching impedance on the two wires (symmetry), and is not always used to carry a balanced signal, just a differential one. A balanced cable rejects common-mode interference whether the signal is balanced or not, but especially well if it drives balanced input impedances and the signal is balanced too.

No, he does not mention the impedance requirement at all in his blurb. You are interpreting words that are simply not there. You are both wrong.

EDIT: I replied too quickly. You are REALLY wrong. A balanced cable used for unbalanced connection picks up MORE common mode noise.

 

[PRR]

"Balanced" (differential) inputs normally connect fine to un-balanced outputs.

Have you tried it?