XLR/RCA - Bridging Pins 1 & 3

[GO-NAD!]

So, I'm building my 2 subwoofers for my 2-channel system. I intend to use a Behringer EP amplifier and a DCX2496. This means that I will need 6 cables:
2 x RCA/Male XLR (Pre-out to DCX)
2 x RCA/Female XLR (DCX to Main-In)
2 x XLR Male/Female (DCX to EP amp)
For an unbalanced connection, the manuel states that pins 1 and 3 are to be bridged.

I intend to order cables from Monoprice and have the following assumptions:

A) The centre pin (+) on the RCA end will be attached to pin/socket 2 (+) at the XLR end.

B) The ring (-) on the RCA end is attached to pin/socket 3 (-) at the XLR end.

Would that be correct? If so, it raises some questions in my mind:

1) What is the purpose of bridging pins 1 and 3? Is it to provide a path to ground through the entire circuit?

2) How does one bridge these pins on ready made cables? Do I have to dismantle the XLR ends to do this, especially on the female connectors?

3) Or, do they come already bridged?

I'm filled with trepidation about using pro components in my system and the more info I can gather beforehand, the better I'll feel about.

Thanks.

 

[highfigh]

So, I'm building my 2 subwoofers for my 2-channel system. I intend to use a Behringer EP amplifier and a DCX2496. This means that I will need 6 cables:
2 x RCA/Male XLR (Pre-out to DCX)
2 x RCA/Female XLR (DCX to Main-In)
2 x XLR Male/Female (DCX to EP amp)
For an unbalanced connection, the manuel states that pins 1 and 3 are to be bridged.

I intend to order cables from Monoprice and have the following assumptions:

A) The centre pin (+) on the RCA end will be attached to pin/socket 2 (+) at the XLR end.

B) The ring (-) on the RCA end is attached to pin/socket 3 (-) at the XLR end.

Would that be correct? If so, it raises some questions in my mind:

1) What is the purpose of bridging pins 1 and 3? Is it to provide a path to ground through the entire circuit?

2) How does one bridge these pins on ready made cables? Do I have to dismantle the XLR ends to do this, especially on the female connectors?

3) Or, do they come already bridged?

I'm filled with trepidation about using pro components in my system and the more info I can gather beforehand, the better I'll feel about.

Thanks.

Pin 1 on XLR is always ground. Pin 2 is signal + (normal) and pin 3 is signal - (inverted). If it's being used for unbalanced audio, pin 3 becomes the signal negative.If you look at the cable itself, you'll see that it has two insulated wires and then it's wrapped with a shield. Pin 1 is the shield and is used for eliminating noise/interference. The other two are used for the signal. The reason they use two separate wires for the signal is that balanced audio doesn't connect the audio negative directly to the chassis ground because long runs cause ground loops. By isolating the audio circuit from the chassis, a couple Ohms of additional resistance doesn't cause hum. Since the equipment is usually in one place when converting from XLR to RCA or 1/4", this isn't usually as much of a problem.

The Behringer manual has this information in it, too.

There's no reason not to use pro equipment in a home system. I put a Behringer EQ and A500 in a bar system that had an Insignia receiver connected to a Rowe jukebox. I needed isolators because the wiring in the building isn't very good but the hum only showed up when I connected the satellite box (that got an isolator) and the jukebox to the equalizer (that got the second isolator). The EQ and amps (a second power amp is used for the patio speakers) are on the same circuit as the receiver with the jukebox and sat receiver on another. There's enough resistance in the power wiring that it caused this problem. If your equipment is on one circuit, you should have no problems.

 

[GO-NAD!]

Pin 1 on XLR is always ground. Pin 2 is signal + (normal) and pin 3 is signal - (inverted). If it's being used for unbalanced audio, pin 3 becomes the signal negative.If you look at the cable itself, you'll see that it has two insulated wires and then it's wrapped with a shield. Pin 1 is the shield and is used for eliminating noise/interference. The other two are used for the signal. The reason they use two separate wires for the signal is that balanced audio doesn't connect the audio negative directly to the chassis ground because long runs cause ground loops. By isolating the audio circuit from the chassis, a couple Ohms of additional resistance doesn't cause hum. Since the equipment is usually in one place when converting from XLR to RCA or 1/4", this isn't usually as much of a problem.

The Behringer manual has this information in it, too.

There's no reason not to use pro equipment in a home system. I put a Behringer EQ and A500 in a bar system that had an Insignia receiver connected to a Rowe jukebox. I needed isolators because the wiring in the building isn't very good but the hum only showed up when I connected the satellite box (that got an isolator) and the jukebox to the equalizer (that got the second isolator). The EQ and amps (a second power amp is used for the patio speakers) are on the same circuit as the receiver with the jukebox and sat receiver on another. There's enough resistance in the power wiring that it caused this problem. If your equipment is on one circuit, you should have no problems.

Thanks a lot Highfigh! So, how do I actually bridge those pins?

 

[WaynePflughaupt]

So, how do I actually bridge those pins?

Most likely you'll find that the cables will come with a jumper between pins 1 & 3. If not, you'll probably find that the shield and the wire connected to Pin #3 will be tied together at the RCA's sleeve connection, which accomplishes the same thing.

Regards,
Wayne A. Pflughaupt

 

[highfigh]

Thanks a lot Highfigh! So, how do I actually bridge those pins?

You can solder a thin jumper from one pin to the other. Just make sure the original wire doesn't move when it gets hot enough to add the jumper. It's not carrying any appreciable current, so it doesn't need to be heavy. You could take a few strands of wire from a scrap of speaker wire, twist them, cut them about 1" long, wrap it around the correct pins and solder it on, make sure the arrangement works before clipping the ends off.