Patchbay question

docz · 18th January 2011, 09:53 AM

Hello folks. I have a question. I'm building a patchbay to use in my studio, it is for easy access to my Liquid Saffire 56, so I am going to build two patch panels using XLR plugs, and I am going to build a stagebox with patch panel to go over my drumkit. Since multicore wire is very expensive, I need some tips on what I can get away with.

First, can I hook all the ground terminals together, and use one common ground wire? Or do all plugs need their own ground wire?

Second, what thickness wire do I need? I can get my hands on some 12 pair 0.19mm2 cable at a nice price. If I need to go to 0.22mm2 it costs 10x per meter.

Cheers,

DocZ

AndrewT · 18th January 2011, 11:11 AM

Hi,
are you working with balanced lines at normal signal levels?

Screened twisted 2core or screened twisted star quad work well at signal levels, if your transmit and receive impedances are correct.

You do not need a lot of copper at the low current levels in line level signal.

What is the resistance of the 0.19sqmm pair for a 100m length?
What is the voltage drop along that 100m length if the peak current is 1mApk?

Speedskater · 18th January 2011, 11:20 PM

The XLR's pin #1 is for the screen (shield), they are connected to the chassis not the audio or circuit ground.

I think that the 0.22mm2 is about 76 Ohm per KM
and the 0.19mm2 is about 84 Ohm per KM.

So from an audio signal point of view, no difference.

Is each pair screened in each case?

18th January 2011, 11:20 PM	#3
Speedskater diyAudio Member Join Date: Sep 2002 Location: Lakewood, Ohio	The XLR's pin #1 is for the screen (shield), they are connected to the chassis not the audio or circuit ground. I think that the 0.22mm2 is about 76 Ohm per KM and the 0.19mm2 is about 84 Ohm per KM. So from an audio signal point of view, no difference. Is each pair screened in each case? __________________ Kevin

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18th January 2011, 09:53 AM	#1
docz diyAudio Member Join Date: Nov 2004 Location: Tønsberg	Patchbay question Hello folks. I have a question. I'm building a patchbay to use in my studio, it is for easy access to my Liquid Saffire 56, so I am going to build two patch panels using XLR plugs, and I am going to build a stagebox with patch panel to go over my drumkit. Since multicore wire is very expensive, I need some tips on what I can get away with. First, can I hook all the ground terminals together, and use one common ground wire? Or do all plugs need their own ground wire? Second, what thickness wire do I need? I can get my hands on some 12 pair 0.19mm2 cable at a nice price. If I need to go to 0.22mm2 it costs 10x per meter. Cheers, DocZ

18th January 2011, 11:11 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, are you working with balanced lines at normal signal levels? Screened twisted 2core or screened twisted star quad work well at signal levels, if your transmit and receive impedances are correct. You do not need a lot of copper at the low current levels in line level signal. What is the resistance of the 0.19sqmm pair for a 100m length? What is the voltage drop along that 100m length if the peak current is 1mApk?