Balanced Connector Question

[Spiritworks]

Regarding TRS and XLR connectors:

I understand that

T = #2 = Hot
R = #3 = Cold
S = #1 = Earth

Is signal ( - ) considered cold , while signal ( + ) is considered hot ?

 

[JohnRoberts]

yes...

2= audio +
3= audio -
1= common

JR

 

[Spiritworks]

Thanks John.

 

[JohnRoberts]

Thanks John.

BTW there are legacy products that were pin 3 hot and pin 2 audio low.  Pin 1 was always common.  I have seen some issues trying to connect unbalanced to old gear where the wrong output leg was hot.

JR

 

[Speedskater]

"JR" if we discussing a single channel balanced interconnect. Then XLR pin 1 is chassis or shield.  It is not part of the audio circuit. It is not audio ground or audio common. With a jack, the pin 1 should be connected directly to the chassis.

 

[JohnRoberts]

Yes...

JR

 

[pucho812]

I think JR knows where pin one goes

 

[Speedskater]

For other reader, this is from a recent Bruno Putzeys paper:

Dealing with legacy pin 1 problems
21/02/2013 - Bruno Putzeys

In a balanced connection, there is no such thing as an “audio ground”. There are just two wires.
The voltage between these two wires is the signal. The input is floating and does not require a connection
between the “audio grounds” of the source and the receiver. That’s the whole point of
balanced connections. You don’t want to rely on the two circuits being at the same potential because
that’s often unachievable.
The third connection, pin 1, is only used to connect the cable shield. If making this connection causes
hum, this indicates a misguided attempt to use pin 1 to connect the “audio grounds”. There is never
a reason to connect pin 1 to directly to your circuit.

http://www.hypex.nl/component/weblinks/weblink/23-application-notes/78-pin1.html?task=weblink.go

 

[Speedskater]

I think JR knows where pin one goes

I've been reading JR's magazine articles since the 1980's but typo's do happen.

 

[Spiritworks]

Thank you. For my purposes, I understood common to be the same as shield/earth.