When wiring my guitar pickup, I connected the ground wire to the ground of the output jack. After hooking that up, I would hear a hum unless I soldered a wire from the metal bridge of the guitar (where the strings enter the guitar body) to the same ground of the output jack. Why did I need to connect the bridge to ground?
Electronic – need to “ground” the guitar pickup to the guitar bridge
acgroundguitar-amplifier
Related Solutions
through 4-wires cable splitting at ~1 mt from the connector.
One meter of thin cable has indeed some resistance. But you can eliminate this almost altogether by splitting close to the connector, which makes the circuit look like this:
simulate this circuit – Schematic created using CircuitLab
Note: R1-R5 are the resistances of the copper cables.
In other words, a shorter common wire will have less internal resistance and thus less crosstalk.
Have you studied the relevant wikipedia page ?
All the way down at the bottom right is a picture which shows you how to connect 6.3 mm stereo and mono jacks.
For a mono connection using a stereo jack, only use the tip (3) and the ground connection (marked (1) ). Leave the (2) connection of the stereo jack open (unconnected).
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Best Answer
The 'ground' of the output jack is actually a shield (and probably connected to chassis ground). It prevents outside electric fields (especially the 60Hz hum) from capacitively coupling into the audio signals inside the cable and jack. By soldering the bridge to the shield, you are extending the shield around the pickups.
Noise can couple into circuits capacitively (via electric fields) or inductively (via magnetic fields). Shielding stops electric fields. Its also good not to turn cabling into an antenna (which could have also been happening with your setup.
Magnetic fields are more difficult because they can only be attenuated by materials. The best thing to do is not create loops which make antennas and avoid mutual coupling (every wire with current creates a magnetic field)
An ideal shield looks like the bottom diagram, since you can't put a shield all the way around the pickups, grounding it is a close second.