7 pin XLR wiring question

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wstratton

Active member
Joined
Apr 2, 2020
Messages
29
Location
Beacon, NY
Hi all,

I have bought some Gotham GAC-7 cabling along with Neutrik NC7MXX and NC7FXX connectors with the intention of soldering my own tube microphone cable for a D-EF47 build. I've soldered a few standard XLR cables in the past, so I thought this would be relatively simple. Now I see that there are seven colored wires (the red and the blue are slightly thicker) in addition to the ground housed in the cabling, which will leave one wire as odd man out if I am soldering the signal ground to one of the contacts. My question is: is there a best practice for which wires to solder to which contacts? I'm assuming I clip the end off of one of the five thinner wires to make room for the ground, but I'm not sure.

Thanks for any advice you may have!
 

RuudNL

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Joined
Apr 26, 2009
Messages
2,408
Location
Haule / The Netherlands
No rule(!), but this is how I do it:
Use the two thicker wires for the filament of the tube. (The filament will take the highest current.)
Use the remaining 5 wires for the other pins.
The screen connects to the connector housing, with a short wire to another pin that is connected to ground.
No wires left or cut, neat construction.
 

wstratton

Active member
Joined
Apr 2, 2020
Messages
29
Location
Beacon, NY
RuudNL said:
No rule(!), but this is how I do it:
Use the two thicker wires for the filament of the tube. (The filament will take the highest current.)
Use the remaining 5 wires for the other pins.
The screen connects to the connector housing, with a short wire to another pin that is connected to ground.
No wires left or cut, neat construction.

Thanks for this!  For anyone who comes across this thread, I also found this info secondhand:

"According to Klaus Heyne the neumann protocol for tube mic wiring is:

conductor 1. white audio +
2. black audio -
3 and 7 thick blue and shield.(ground)
4. thick red heater.
5. yellow 120volts
6. green 0-120volts
and the 7th grey conductor is cut short and isolated."
 

rockinrob86

Well-known member
Joined
Mar 9, 2015
Messages
233
Location
Tampa, FL
I hate making normal cables, just finished about 200 for my patchbay setup. 

As much as I hate making regular cables, I REALLY hate making tube mic cables!

I wire audio ground and chassis ground separately and only connect the shielding on the power supply side
 
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