So far we’ve looked at why you might want to alter your sound with pedals, and outlined a sensible approach to discovering which pedals might be relevant to you. I’ve covered how multi effects units aren’t completely useless, but that few people stick with them, they don’t hold any re-sale value, and as such aren’t where you want to spend the bulk of your gear budget.
If you’ve been following so far you’ll probably have a few pedals and have plugged them in and started having fun with them. It’s time to start thinking about power solutions.
Powering pedals can be fairly impractical. You’ll either go through a lot of 9 volt batteries or have a comical arrangement of wall-wart power adapters. Surely this isn’t what the pros do?
There are of course more practical solutions. Before we get into those, we’ll need to pause for a moment and get a boring but essential bit of science out of the way. When plugging a power lead into a pedal you always need to consider four things:
Voltage, Current, Polarity, and Isolation
Voltage
Most pedals operate at 9 volts, some require more, and some can take more (eg overdrive pedals with different amounts of headroom available). Not providing enough voltage might not damage your pedal, but it will quite likely sound horrible. Providing too much voltage will almost certainly fry your pedal. Before you power up a pedal, be sure of its voltage requirements.
Current
This is a simple concept which confuses many. Current is measured in amps (A) or milliamps (mA), and is a way of measuring how thirsty a device is, not a limit on how much electricity you can throw at it. The mA requirement of your pedal is the minimum it requires to function, and likely how much it will draw from your power supply.
It is perfectly safe to connect a 200mA power supply to a pedal requiring 100mA. The power supply will make 200mA available, but the pedal will only take the 100mA that it needs. If a power supply doesn’t provide enough mA, the pedal won’t function properly or even turn on. Best practice is to have your power supply offer more mA than your pedal requires.
Polarity
Like the tip and the sleeve on your audio cables, power cable connectors have two separate parts to consider. They will either be centre positive or centre negative.
Most pedals will be centre negative, but occasionally (like with some old Proco Rats) you’ll get one that’s centre positive. Be sure of which way around your power lead is, and which way your pedal is designed. If you get this wrong your pedal will either simply not turn on, or end up completely fried. Toss a coin. Whatever the outcome, you’re not going to be using that pedal today.
Isolation
This refers to making sure your pedals don’t share a ground connection.
Pedals often use their ground connection like a sewer line. They dump certain audio frequencies (like the clipped part of your signal in a drive pedal) by sending them to ground. If you hook your pedals up so they share a ground connection (think “pedal sewer line”), these audio artefacts, along with some electricity, could end up being reintroduced to the audio signal of other pedals in your chain. Just like you wouldn’t want your neighbours’ sewerage backing up in your house, your pedals don’t want to be awash with crap from other pedals in the chain.
This could result in anything from a mild, low level hum all the way through to crazy, high-pitched, whistling oscillation noises which can be tricky to troubleshoot.
For example, some folks will complain that a delay pedal at the end of their chain is making a weird noise, when in fact a fuzz pedal at the start of the chain is generating it. It might just be that only the delay pedal is picking it up and making it audible. The solution is not to remove the fuzz or the delay, but to make sure they’re not sharing a ground connection.
So What Should I use?
Daisy Chains
The first thing most rookies try, no doubt because of the low cost and simplicity of it all, is to daisy chain your pedals. This involves one power adapter which plugs into a series of connected cables. This might work for some pedals some of the time, but is generally considered a horrible idea.
All of your pedals are drawing their power from the one source, potentially under-powering them, leading to them not functioning correctly and not sounding quite right. The more noticeable problem though is that they all share an earth connection which could lead to audio interference between pedals (see isolation section above).
If you insist on doing this, you can get away with it under some circumstances. I’d maybe consider it if you have a simple pedal board with only a tuner and a drive pedal or two.
Mixing digital and analogue pedals seems to be the main issue. I believe analogue pedals tend to generate most of the noise in a shared ground connection, while digital pedals pick it up and make it audible. While we’re at it, digital pedals should probably be isolated from each other too. When it comes to power, they just don’t play well with others.
Of course, make sure the adaptor at the start of your daisy chain is providing the correct voltage and enough current for all of your pedals. You’ll typically want a 9v adaptor with a crazy high current. Add together the mA draw of all the pedals you’re going to daisy chain, and make sure the power supply can offer at least that much, preferably more.
1 Spot are the kings of daisy chain solutions, while most other budget pedal brands like Mosky, Donner, and Joyo tend to have something on offer.
Power Bricks
You can buy a power “brick” which takes up only one wall socket space, will convert your AC mains power into DC power at the correct voltage for your pedals, and will have multiple outlets for your pedals to plug into.
They vary massively in price, so let’s have a quick look at what you’re paying for and which features might be important to you.
Some bricks provide surge protection, and most should provide clean, regulated power to your pedals.
The main thing which separates the cheap power supplies from the expensive ones is isolation. The whole point of getting one of these is to provide isolated power to your pedals, so it makes no sense to get one which doesn’t. There are inexpensive ones which are nothing more than a tidier version of a daisy chain solution, offering no isolation whatsoever.
Maddeningly, some claim to be “isolated” while not actually being isolated in the sense we’re thinking of. The power supply itself is isolated from other devices, sure, but we want each of its outputs to be isolated from each other. Look for the words “isolated outputs” or something like that. Don’t be content with merely seeing the word “isolated” in the product description.
The number of outputs will have an impact on the price. Get one with more outputs than you think you need. I don’t care if you think you have all the pedals you’ll ever need to power up, I know you’re lying to yourself even if you don’t. If you get a five outlet power supply, don’t come crying to me when pedal number six shows up and you have nowhere to plug it in.
However much you save by getting the smaller power supply, think of how much more expensive it will be when you have to buy a second one. It will happen. You’ve been warned.
Some will come with a few outputs which are a higher voltage. This can be handy if you have pedals which require more than 9 volts, or it could be a waste of an output if you don’t. Some of these will be switchable between 9 volts and 12 or 18 volts, which is the best option. Just make sure you’re not paying for a power supply with outputs you can’t use.
Just like with the daisy chain solution, you’ll need to figure out how much current you need. Add up the mA of all of your pedals, and make sure the power supply you get can deliver equal to or greater than that amount. There’s no point getting a power supply with over 20 outputs if it only has enough mA to drive one pedal.
Also consider the size of the power supply. If you intend on sticking it underneath a pedal board, you need to make sure it will fit.
It used to be the case that no modest budget power bricks were isolated, and if they said they were, it was mere marketing trickery. That’s not the case as much these days. Check the specs and read reviews. You’ll find many units where someone has bought one and tested the outputs with a multimeter to confirm if they are indeed isolated.
At the budget end of the spectrum, have a look at Caline and Mosky. At the more mid-priced to professional end have a look at:
Probably one of the most expensive yet best value power supplies on the market is from GigRig. They provide a modular solution, meaning when you run out of outputs, you’re not stuck having to buy a whole new power supply. You can simply buy another adaptor with more outputs and plug it into an output of the unit you already have.
To kick start the whole thing, you buy their “Generator”. This provides clean, regulated, surge protected power at a whopping 5 Amps. From there you plug in a “distributer” which gives you 4 outputs. Into each one of those outputs you can plug in an “Isolator” which each provide 4 isolated outputs. This results in 16 isolated outputs. If pedal number 17 ever turns up you can get another isolator and plug it into one of the outputs of one of your other isolators.
GigRig pride themselves on being the best in the business when it comes to durability, quality control, aftermarket support, and most importantly making sure your guitar tone remains pure and untainted. For the record, I don’t have an affiliate marketing arrangement with the GigRig. It’s common knowledge in the industry that GigRig is the Rolls Royce of pedal power supplies.
Next time we’ll look at pedal boards themselves, patch cables, and a few things to look out for when putting it all together.
Tone Quest 