There’s nothing more troublesome or worrying for an electric guitarist than hearing strange noises coming from their amplifier.
We’re musicians, not technicians…
How do you know what is causing the issue?
In this article I’m going to give you some guitar amplifier noise troubleshooting tips so you can safely and effectively get your amp back into working order.
Always remember, guitar amplifiers hold large amounts of voltage and can kill you. If you don’t know how a guitar amp works, consult your local technician. Keep the following in mind when troubleshooting amp noise:
- Be aware of high Voltage within amplifier
- Allow Amp to discharge by unplugging for 15 minutes before working on it
- Wear rubber gloves for extra protection
- Always keep the amp off while working inside it
Normal Guitar Amp Noises
If you are new to guitar amplifiers, especially tube amps, you may be thrown off by the natural humming that these analog amps create. Rest assured, a low, steady hum from your tube amp is quite normal.
This is called the noise floor, and every tube amp has it.
Typically speaking, the noise floor will momentarily disappear once you start playing your instrument.
Another thing worth mentioning is that higher wattage (aka higher power) amplifiers will create a louder noise floor than small, low-wattage amps. Higher gain amplifiers/channels will also create more natural noise than clean amps/channels do. Noise Gate or Noise Suppressor pedals are a quick and easy fix if you play a lot of high-gain music.
High-quality, solid state amplifiers, on the other hand, typically produce less hum as long as they are fed clean power. However, high-gain settings are still likely to create some kind of noise due to your guitar’s pickups.
Abnormal Guitar Amp Noises
Now for the noises you don’t want to hear coming from your amp.
While a light hum is perfectly normal, if you hear clicks, pops, hissing, buzzing, radio stations (yes, it happens) or microphonic sounds coming from your amp, then you have a problem.
Not only do these symptoms sound horrible, they can be a sign that something is detrimentally wrong with you amplifier and should be addressed as soon as possible.
Let’s take a look at some of the common causes for these sounds so that we can properly troubleshoot the issue and fix your noisy guitar amp.
Causes of Guitar Amp Noise & Solutions For It
There are many different things that can cause noise in your amplifier. Some have specific cues that you can easily identify, while others require more of a “trial and error” approach.
I recommend removing all pedals from your signal before troubleshooting, as pedals can introduce noise (and you may have found your culprit!)
Here are some common causes of guitar amp noise to get your search started.
1. Your Guitar’s Pickups
This is one of those noises that is considered “normal”, but it can still be troublesome, especially with single coil pickups. Electric guitar pickup manufacturers have been trying to eliminate noise from pickups for decades.
Case and point: the Humbucker.
This pickup consists of two single coil pickups wired in parallel so that that their phases cancel each other out, effectively “bucking the hum”.
If you have single coil pickups, the natural “60-Cycle Hum” may be a natural sound that you have adapted to. However, there are also many noise cancelling single coils out there.
All of these pickups typically emit some kind of noise from them. Some two-pickup guitars eliminate almost all noise when you switch to the middle position and you can use this as a troubleshooting technique.
2. Lights/Cell Phones
A new issue for guitarists is the introduction of cell phones around our electric guitars and amps. Many of us use our phones for charts on stage.
It turns out that the frequencies emitted from our cell phones can cause interference and hum through our amps.
Fluorescent lights and light dimmers also cause this similar issue. You may notice that your amp is especially noisy at home or on a particularly well-lit stage. If this is the case, it may be due to the electrical devices around you.
It’s best to keep your cell phone off of your amplifier entirely. Often, when I hear my amps being particularly noisy, the first thing I do is check my pocket to see if my cell phone is in it and leaning up against my guitar.
More often than not, putting my phone away (usually off in my guitar case) eliminates the pesky noise.
Lights can be more tricky, as you can’t always fully control your environment. There may be a room in your house that has better electrical wiring, or perhaps you can take the dimmers off of your light sources. Noise cancelling pickups can help fight this issue.
Also, you can turn your body to a particular angle, and you will notice that the hum fades away. This is what I like to call the “sweet spot”.
3. Ground Loop/Isolation Issues
Plugging your amplifier into a different circuit than the rest of your rig can cause a loud hum to come through your amplifier. This issue can even persist if everything is plugged into the same outlet. Grounding issues are the plague of sound engineers and musicians everywhere.
This is also a good time to mention your guitar pedals, which can introduce a ton of noise if they aren’t powered with their own, isolated power source. Read this article to make sure you get a great pedal power supply to reduce noise.
No matter what you do, NEVER lift/remove the ground from the electrical plug. This can eliminate your issue, but you are much more susceptible to electrocution.
There are a few ways you can fix Ground Loop issues. The easiest and cheapest is to first plug everything into the same outlet.
If that doesn’t fix the issue, you can try hardware filters like the Hum-X. With this kind of device, your amp can be on a separate circuit and the hum will still be eliminated.
Isolators are another form of hardware that can combat ground loop/balance issues. Be sure to buy a power supply that you don’t daisy chain your pedals. Rather, individually isolate/power them with a good power supply.
4. Dirty Power
Old buildings often have old electrical wiring that can have breaks or other issues, creating what we call “dirty power”. This is one of the most common reasons for guitar amp noise. Not only can it be a problem if you live in an old home, but it can sneak up on you if you play a gig at an older venue.
The easiest way to fix/eliminate this issue is to buy a power conditioner. Furman is one of the most well known and trusted power conditioner manufacturers by musicians and I highly recommend you bring either their floor conditioner or rack unit to every gig.
5. Bad Tubes
For tube amp troubleshooting, if you have eliminated all of the above situational/everyday noise causing issues and you play through a tube amp, abnormal amp noise is almost always due to a power tube that has gone bad.
Replacing your tubes is a normal part of tube amp maintenance, which is why you should always bring spare tubes with you to gigs. I wrote an article on what I believe are some of the best tube amps on the market which I recommend you read.
If you are experiencing microphonics, you can isolate which tube they are resonating from by tapping on the tubes with the amplifier on. If the tube rings, that’s the bad tube. You can then turn the amp off, follow the safety measures above, and replace the tube.
If you are experiencing crackles, hissing, or pops, then you may need to troubleshoot each individual tube by swapping each tube out.
If increasing the volume of the amplifier increases the noise issue, then a preamp tube is your culprit. If not, then it’s a power tube issue.
You can also apply this method to multi-channel amplifiers. If the noise persists on one channel and not the others, then you have a preamp tube issue. If it goes across the board, it is a power tube issue.
Finally, if your amp has a reverb circuit in it powered by a tube, this can also go bad. Try turning the reverb volume up/down to see if any noise persist and then replace the tube if so.
Go One Step At a Time
There are a lot of things that can cause noise in your amp. It is their job after all to make quiet noises louder.
However, if you trouble shoot guitar amp noise step by step through the most likely culprits listed above, you will more than likely find your issue and you can get rid of the excessive hissing, buzzing or humming sound on your own.
If none of these work, I recommend turning your amp off and taking it to a professional.
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Davis Wilton Bader is a professional guitarist/writer based out of St. Louis, MO. He plays in the bands Lumet and The Outskirts.