Why does my amp buzz when I touch my guitar strings?

Updated July 11, 2018

Buzzes and hums are the bane of electric guitar players everywhere. An underlying, electronic murmuring can be irritating when you’re practising and a constant source of trouble when you’re playing live. Most buzzing from the guitar will get quieter when you touch the strings, but this isn’t always the case. Understanding why the buzzing may get louder when you’re making contact with your strings and learning about the most common reasons it’s become a problem gives you an idea of how to rectify the issue.

Pickups and hum

The pickups are the most important element of the electric guitar. Instead of sound bouncing around in the cavity of the instrument (as with an acoustic guitar) when the strings vibrate, electromagnetic “pickups” sense the fluctuation they produce in the magnetic field. This is creates a variation in the strength of the signal going through your guitar and (after being amplified – because the signals produced like this are very weak) replicates the instrument’s sound. Single coil pickups are particularly prone to picking up interference from electronics in the nearby area and creating a humming sound, but the dual-coiled humbucker style pickup was invented to solve this issue.

You are not silent

This basically means that an electric guitar measures electromagnetism, not sound and it is prone to interference for that reason. Even you are a potential source of interference, because the human body is not magnetically “silent.” That’s why grounding is so important in the internal circuitry of the guitar. This filters away excess current to prevent it from interfering with the signal. Ordinarily, the grounding on the strings (which usually runs from the bridge to the volume and tone dials) will take any excess current they pick up away so they don’t interfere with your signal, but this isn’t always the case.

Non-grounded strings

If you touching a string causes an increase in noise from your amplifier, you may be creating a current in the string which is being detected by the pickup. This means that your ground wire is either missing, damaged or has disconnected. Open the cavity for your “Volume” and “Tone” controls if you want to check. See your manufacturer’s website for information specific to your make of guitar. There should be a wire coming from the bridge (or tremolo bar) of your guitar to the volume pot. If you have a soldering iron, you may be able to re-connect the wire if it isn’t attached or attach a new one if it isn’t there.

Output jack wiring

In some cases, buzzing which increases when you touch the strings could be a result of the wires going to the output jack being connected incorrectly. This can usually be removed by unscrewing the screws on either side of the jack, but you can check your manufacturer’s website if they aren’t present. The problem may be that the “hot” (signal) wire is attached to the ground point on the jack and vice-versa. The ground point will be short and attached towards the middle of the jack. Ideally, any tinkering with the electronics should be done by a professional.

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About the Author

Lee Johnson has written for various publications and websites since 2005, covering science, music and a wide range of topics. He studies physics at the Open University, with a particular interest in quantum physics and cosmology. He's based in the UK and drinks too much tea.