So the question should be, “where is the humming, buzzing noise coming from in my system?” To simplify this problem, it’s a good idea to break the system down by isolating the various components so you can find the source of the noise.
Checking The Guitar For Noise
Most likely, the culprit is your guitar, so check that first. Unplug your pedals or bypass them and go straight to the amp, turn up the volume on the guitar and listen for the noise. If it’s there, turn down the volume and if the noise goes away, it’s your pickups.
Single coil pickups are renowned for picking up noise, and manufacturers go to great lengths to design low noise or noiseless pickups due to this problem. Switching to a Humbucking pickup will reduce the noise, confirming again that the guitars pickups are the cause.
However, there is an acceptable level of noise tolerated from pickups and if this level is reasonably low then you will have to live with it. If it’s excessive, you may want to get a Luthier to offer some advice on reducing those noise levels.
Leads And Pedals
Guitar leads generally work or don’t work, so if your lead hums it probably won’t work either. Get it repaired if it’s a good quality one, or use another.
A lot could go wrong with pedals, due to the multitude of electronics in so many little boxes, each with connecting cables and usually a common power supply operating all of them at once.
Noise from your pedals may be coming from an over-burdened or poorly regulated power supply, introducing hum into the system. If this is the case, check the power supply’s capacity to see if it can handle the total power requirements of all your pedals.
Your pedal itself may be faulty (check by physically removing each pedal from the system one at a time) or it may be one of the connecting leads that is causing the issue. It’s a good idea to occasionally push connecting leads in and out of each pedal. This will give them a clean in case there is some corrosion build up in the pedal sockets. Other noise problems with pedals could be put down to poor pedal location, i.e. hum sensitive pedals like Wah or distortion pedals being located too close to a noisy power supply, etc.
Checking The Amplifier For Noise
This procedure will systematically allow you to check the various section’s of the amplifier to locate the source of the noise.
The first thing to do is to remove the guitar lead going into the input of the amp. This will allow you to check the amp for noise in isolation.
Turn the amps Master Volume and Gain controls to off or zero with the speaker plugged in and then turn the amp on and listen for the noise.
If the noise is there it’s being made by the power section of the amplifier, possibly by a bad tube, transistor or a power supply component like a capacitor. If the noise is not there with the volume and gains turn down, turn the master volume up and if the noise appears, then there is a fault with the preamp section of the amp, possibly a noisy valve.
If there is still no noise when you turn the Master Volume up, leave it up and now turn the Gain control up. If the noise appears, the problem is to do with the input section of the amp, possibly the first valve or even the input socket. Also, if the amp has reverb, turn its control up and if the noise appears then there may be a problem with the reverb unit (or the connections to it).