The dreaded hum that hinders recording and spoils live performances generally manages to annoy even the most mellow of musos. So, is there a real solution to this problem?
There are lots of tips and guides available online that promise you a clean and ‘hum-free’ sound. The good news is that it’s usually something simple and easy to resolve. You do not need to have a degree in electrical engineering, although it wouldn’t be so bad to have one!
To sum it up quickly (before we get into the details) – the most common reason behind humming issues is the 60-cycle hum, sometimes called a ground loop. And the most common culprit is the power supply. It’s easy to fix it and get rid of that pedalboard hum.
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Your Pedalboard Setup
Not all pedals were created equally – different types of pedals require different power supplies. We all know that analog is the better choice but let’s keep that tiger caged for now. You have your analog pedals that produce sound using valves, circuitry, and other sources of ‘natural’ sound production.
Digital pedals, like digital pianos, create a synthetic sound, and they usually draw more power than the analog version. Between these two options, you have created your rig using patch cables and more than likely a daisy chain power supply.
You switch on and there it is – the hum. Don’t despair and please don’t throw it out of a window. Just keep reading.
The 60-Cycle Hum and Ground Loop
Without being too science-y – electricity (AC current) alternates at 60Hz in the United States, which is probably why the hum is referred to as the ’60 cycle’ hum. Every single appliance plugged into this power source emits its own electromagnetic field, or EMF for short.
These EMFs created by nearby appliances such as fans, heaters, desk lamps, and home entertainment systems, interfere with the audio system of your rig, which also creates an electromagnetic field of its own.
Make sure that your pedal rig patch cables and power supply are not in contact with any other appliances or power cables. If that doesn’t work, try moving away from other electronics like your laptop, or a television set. Basically, move around in your space and find the ‘clean’ spot.
The Ground Loop Problem
Think about this: The amplifier and mixing desk at the venue are quite far from one another, and both are grounded via the mains earth pin. The same goes for your pedal rig, instrument, and other gear connected to a power supply.
To fix this, the performance venue uses a ground lift switch that breaks the loop and cancels the hum. Alternatively, the venue can connect both the source and destination through an isolation transformer or iso coil. This is also referred to as a humbucker.
There is also the extreme solution – breaking of the ground pin at the power supply of the desk or using an AC ground lift adapter. If this is the solution the venue comes up with, you should probably leave, or at least inform your family of your approaching demise.
But this should hardly be your problem, so don’t get freaked out now. The venue deals usually take care of this
Power Supply Problems
Cheaping out when it comes to power supply is a terrible idea. Your go-to daisy chain cable that you picked up for $1 at the local electronics store will not cut it. You can also throw away the fancy power supply with the blue LEDs which so proudly claims to be ‘Made in China’.
Remember that different pedals that you own do not use the same amount of electricity. Using a daisy chain to connect all of your pedals will definitely create a lot of noise because there is no way to regulate the amount of power each pedal needs.
So, connect your pedals in any way you see fit, but use separate power supplies if possible. This, of course, is not always practical or even possible, depending on your setup. You can try keeping it down to two pedals per power supply or switch some to battery power.
You just want to make sure that each pedal gets exactly what it needs to work properly. Speak to your musician buddies and spend some time at a good music gear store before you set up or change your rig.
Poor quality patch cables and sound cables will also create a hum. It is pointless to have your pedal rig set up perfectly with regards to power supply and quality products, and then you go as cheap as possible on the cables.
Regularly check your cables for damage or wear and replace as and when necessary. Always try to use cables from the same manufacturer too (i.e. don’t mix and match).
Keep It Short
Avoid long patch cables as much as possible. Short patch cables will make your pedals look neat and will avoid the possibility of contact with other gear that could cause noise, e.g., power cables.
Which Cables Work Best?
Make sure that you use high-quality cables such as Mogami or Pro Co. I’m not saying these are the only cables worth having, but at least try out some different options and make sure you don’t go for the cheapest option simply because it fits your budget.
Troubleshooting to Identify the Problem
You could also run through all your pedals separately to determine if any specific pedal is causing the hum. This could be due to a defective pedal or wear and tear. Then, unfortunately, it’s time for replacing.
It hardly feels fair to leave it here. There are so many possible issues with just as many possible solutions, but it is impossible to cover everything without having the opportunity to physically hear and experience the hum that’s been bugging you.
Try the fixes I’ve come up with and if that doesn’t work, don’t give up. Speak to an expert and use the opportunity to learn.