Old Music Guy
Well-known member
I'm coming in *way* late to this thread. My tuppence...
For the moment, let's put earth or ground aside. Think of your guitar as a radio. The strings are antennae, the pickups are the receiver(s). This is electromagnetic phenomenon i.e. RF. The pickup is essentially a transducer, insofar as it converts the electromagnetic energy (RF) from the strings and converts it to a voltage, i.e. signal. That "signal" then follows the signal chain. It's amplified through the chain, and ends up at your ears as hum. With a spectrum analyzer (free apps available for phones and tablets) you can identify the frequency of the noise. In the UK, it will likely be 50Hz with varying degrees of 2nd and 3rd degree harmonics. 60Hz in the US. The line frequency also has the closest proximity and the highest electromagnetic radiation (EMR).
The reason that putting your hands on the strings attenuates the noise is because your skin has a resistance, i.e. "R". Albeit a high resistance, >100k ohms/sq in/cm. It is this resistance that changes the essential "wavelength" the string is most efficient at receiving. (Think HAM radio, full wave, 1/2 wave, 1/4 wave/ 1/8 wave).
Bottom line is that ANYTHING that emits an electromagnetic field WILL interfere with your stuff. Everyone knows why "humbuckers" were invented.
Just my tuppence.
EDIT: Ever wonder why an acoustic guitar with a piezo saddle pickup doesn't hum?
For the moment, let's put earth or ground aside. Think of your guitar as a radio. The strings are antennae, the pickups are the receiver(s). This is electromagnetic phenomenon i.e. RF. The pickup is essentially a transducer, insofar as it converts the electromagnetic energy (RF) from the strings and converts it to a voltage, i.e. signal. That "signal" then follows the signal chain. It's amplified through the chain, and ends up at your ears as hum. With a spectrum analyzer (free apps available for phones and tablets) you can identify the frequency of the noise. In the UK, it will likely be 50Hz with varying degrees of 2nd and 3rd degree harmonics. 60Hz in the US. The line frequency also has the closest proximity and the highest electromagnetic radiation (EMR).
The reason that putting your hands on the strings attenuates the noise is because your skin has a resistance, i.e. "R". Albeit a high resistance, >100k ohms/sq in/cm. It is this resistance that changes the essential "wavelength" the string is most efficient at receiving. (Think HAM radio, full wave, 1/2 wave, 1/4 wave/ 1/8 wave).
Bottom line is that ANYTHING that emits an electromagnetic field WILL interfere with your stuff. Everyone knows why "humbuckers" were invented.
Just my tuppence.
EDIT: Ever wonder why an acoustic guitar with a piezo saddle pickup doesn't hum?
