How to build a DIY XLR sniffer.
The XLR Phantom Power Sniffer is one great tool to use on a stage when handling live shows.
If you're into the live sound work, this one is for you.
This small tool will help you test cables by solely using the phantom power of a mixer console, in a way, that you'll get two leds lit on the sniffer if all is well with the cable, only one led lit if one of the signal conductors is broken or no leds lit at all if either you have a problem with the console phantom power or the ground connection of the cable is broken.
All you'll need is:
1 - soldering iron
2 - (2) 3mm leds 3mm, 2.2 V forward drop
3 - (1) Male XLR plug
4 - (1) BZX85C24 zener diode 1.3W 24 Zener Voltage
5 - (1) BZX85C18 zener diode 1.3W 18 Zener Voltage
Be aware that before you start soldering the components inside the plug, you should try out the pins length and check the polarity of the diodes. The best plug I could find to fulfill this project was the Neutrik NC3MX 3-Pin M Cable MT XLR.
Without going into to much technicalities, you can follow the schematic below to get it done.
The pins of the leds and diodes can be soldered directly on the plug so you can fit it all inside.
On the first model, I cutted the black plastic on top to be able to check both leds easily.
For you to try it out, connect the plug to a XLR mixer input and feed it phantom power. If all is well done and the console is working, both leds should light up.
If you'd like to get a more detailed description on how this sniffer works, you can go here.
Of course, if you don't have the skills needed to build this project, or just are not into the DIY so much, there are some commercial solutions available such as the SoundTools XLR Sniffer/Sender, which is made of two plugs to allow you to test the cable without using a console.
This is an amazing tool, which besides checking the continuity of the cable conductors, it also detects inverted connections, when testing the cable with both the SoundTools sniffer and sender.
If you have any comment or question, drop a comment below and let me know if you have any other solutions for this purpose.
More on the the sound matters.
- DIY Phantom Power Sniffer
A detailed article on how this Phantom Power Sniffer works.
What's your gear?
What models do you use to test your cables?
© 2015 João Pereira