In an electric guitar or bass, it's usually necessary to 'ground' the strings.
By this, I mean that all the strings should have a path to ground — a wire that connects them to a ground point inside the instrument. Usually that ground point will be the back of a pot or the sleeve of the output jack.
When it's properly grounded, you can touch the strings of your guitar and you'll usually hear the background hiss reduce. Yay.
There’s a common misconception that by touching the strings you are grounding the guitar.
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