Although spending money on power supplies certainly isn't the top of every guitarist's priority list, if you're a heavy pedal user, it's some of the most important money you can spend on your rig.
Most players start with a cheap and cheerful daisy chain, or a generic multi-output adaptor, and while this can see you through to bigger stages and bigger pedalboards, sooner or later it will be time to look at upgrading.
The main reason for upgrading is reducing noise in your signal chain. Hum or buzz in the chain is almost always as the result of power-line noise. Some will be introduced at the amplifier, but a lot of the noise introduced by pedals can be removed.
Individual pedals, especially distortions and digital delays, are likely to have some kind of power-line filtering, but without an isolated power supply - that is, one where each output powers one pedal only, and the power lines do not cross - it's possible to pick up noise from other pedals sharing the same power source.
Another benefit of isolated outputs is knowing that the current delivered to a pedal will be consistent - particularly important with digital pedals. For a non-isolated, parallel or daisy-chain power supply, the supply will be a single mA (milliamp) or A (amp) rating divided between the outputs, whereas an isolated supply will be able to deliver up to the maximum specified on each of its outputs.
Current draw is a major issue. Digital pedals, especially multi-effects or power-hungry DSP platforms like the Boss DD-500 or Strymon line, require a lot of power to operate. On a smaller power supply or a daisy chain, these pedals might not have enough current to operate properly.
In addition, some older pedals like the now-discontinued DigiTech Whammy IV not only require a whopping 1.3A, where most pedals are rated in mA, but also require AC rather than DC, like most pedals. Luckily, some higher-end power supplies have your back even in this unusual case.
Common to almost all power supplies is a general assumption that most pedals will draw around 9V of DC, and that they will accept a centre-negative tip on the power lead.
With that in mind, let's take a whistle-stop tour through the best power supplies available...
1. Truetone 1 Spot CS12
The best pedal power supply for sheer versatility
Launch price: $269/£195 | Type: Isolated power supply | Isolated outputs: 12 | Switchable voltage: Yes | Weight: 1.06kg | Features: Mounting kit, 1 4-9V out, 2 18V outs, 2 high-current outs, 1 9V AC out
Surprisingly affordable given the performance on offer, the One Spot Pro range, which consists of the CS7 and CS12, are fully isolated power supplies with a number of nifty features. The CS7 has six 9VDC outputs, including two high-output 500mA outs for high-draw digital pedals, as well as a seventh output that delivers 18V. On the CS12 there are six 9V outputs from 100mA - 250mA, one 4-9V variable output, 2 high-draw 9V outputs, and 2 18V outputs that can be used for distortions or overdrives that can take 18V for higher headroom. Uniquely to the CS12, there's also a 9V AC output, which can drive older Whammy and DigiTech pedals. Although the rated output is too low for a Whammy, the reality is that a Truetone Pro can deliver up to its maximum current draw, which is the sum of all its outputs, meaning it can flex up if you're not at the maximum for all the other outs.
2. Voodoo Lab Pedal Power Digital
The top choice for high-output digital pedals
Launch price: $139/£165.60 | Type: Isolated power supply | Isolated outputs: 4 | Switchable voltage: Yes | Weight: N/A | Features: Temperature-controlled fan
The Voodoo Lab Digital is a power supply exclusively aimed at powering high-current digital pedals, so if you're in need of a second or extension power supply and you find that you've got a number of high-current digital effects to power, then it could be a good fit. It's pricey, but the specs speak for themselves.
3. MXR Iso-Brick
A compact fully isolated PSU
Launch price: $214/£199 | Type: Isolated power supply | Isolated outputs: 10 | Switchable voltage: N/A | Features: 2 9V DC 100mA outputs, 2 9V DC 300mA outputs, 2 9V DC 450mA outputs, 2 18V DC 250mA outputs, 2 variable 6-15V DC 250mA outputs
The MXR DC brick has a lot of outputs for its size - 8 9V and 2 18V outputs, as well as short and overload protection, although it's obviously not isolated. That's where the somewhat dearer Iso-Brick comes in. The Iso-Brick's ten outputs are fully isolated, and there's a variety of different current draws on offer to drive even the most hungry digital pedals, as well as two 18V outs for higher-headroom distortions and two variable outputs, which can be used to emulate starved-battery sounds on fuzzes. If you don't need all 10 outputs, it's also available in five-output form as the even more compact Iso-Brick Mini.
4. Truetone 1 Spot
The best cheap power supply
Launch price: $24.95/£19.99 | Type: Wall wart power supply | Isolated outputs: 1 | Switchable voltage: N/A | Weight: N/A | Features: 1.7A total output, can be daisy-chained
For a compact power supply that will drive even the most demanding digital effects, you can't go far wrong with the One Spot. The main USP of this simple PSU is that many of them can be lined up on the same power strip - ideal for power-hungry effects or studio use.
5. Cioks DC10
This Danish power supply does it all
Launch price: $209/£209 | Type: Isolated power supply | Isolated outputs: 8 isolated sections, 10 outlets total | Switchable voltage: Yes | Weight: 1.06kg | Features: 15V option for Radial Tonebone pedals, Stack Flex cable can be used to power 18 or 24V pedals, mounting bracket included
Based in Denmark, Cioks has several power supplies in its own range, and also makes the PowerFactor for Eventide. The DC10 is the sort of supply that would be well suited to a medium-sized pedalboard. It has no fewer than 10 outlets in eight isolated sections - outlets seven and eight share the same ground, as do nine and 10. We like the Swiss army knife approach of the DC10, in that it seems to be designed to take on any pedal (including 15V Radial Tonebones), and comes with all the cables you need - so it's ready for action straight out of the box.
6. Pedaltrain Spark
The best power supply for Pedaltrain pedalboards
Launch price: $199/£188 | Type: Isolated power supply | Isolated outputs: 5 | Switchable voltage: N/A | Features: Pedaltrain mounting kit, 2 9V DC 500mA outputs
The Pedaltrain Volto was revolutionary when it first appeared, being a decent power supply that was both truly portable and rechargeable. It featured heavily in the excellent Coffee & Riffs location-filmed YouTube series by the pedalmakers behind Old Blood Noise Endeavours, and facilitated a number of their sessions. The Spark, meanwhile, is a more straightforward power supply with a super-thin form factor that means it can be mounted under smaller boards like the new Pedaltrain Nano series. It features short circuit protection, output regulation and filtering - as you'd expect at this price point - and worldwide switching.
7. Strymon Ojai
A small isolated power supply with killer features
Launch price: $149/£149.95 | Type: Isolated power supply | Isolated outputs: 5 | Switchable voltage: Automatic | Weight: 130g | Features: Chain additional units
Strymon isn't messing around when it comes to its power supplies. Designed to supply the Strymon line, their default current delivery is a whopping 500mA on every output. The Ojai in particular has a really interesting USP - a growing pedalboard can be accommodated using the 24V through connector to connect additional Ojai units, without the need for extra plugs to the wall. In addition, it comes in an R30 variant which is essentially a low-profile version to fit under tighter or smaller boards like the Pedaltrain Nano series. The Zuma is basically a larger, more powerful version of the Ojai. Although it can't daisy-chain to itself, it can supply out to an Ojai, which can then connect to multiple Ojais in a modular fashion. The Zuma also comes in an ultra-low profile version, the R300.
8. Voodoo Lab Pedal Power Mondo
The best power supply for big pedalboards
Launch price: $249/£354 | Type: Isolated power supply | Isolated outputs: 12 | Switchable voltage: Yes | Weight: 1.3kg | Features: 2x12V outs, 2 'sag' outs, Fan
The Mondo's little brother, the 4x4, is a useful supply for the guitarist running a number of power-hungry digital effects, as it has 4 standard outputs, rated at 100mA, as well as 4 400mA outputs, with 2 switchable up to 12V. Both the 4x4 and the Mondo also have a temperature controlled fan to stop the unit overheating in difficult conditions, like a hot festival show or basement gig. The Mondo is essentially just the bigger brother, with more outputs, features and two additional 'sag' outputs that emulate the reduced headroom and voltage supply of a dying battery.
9. Mission Engineering 529
Power your pedalboard via USB
Launch price: $155/£199 | Type: Isolated USB power supply | Isolated outputs: 5 | Outputs: 4 150mA 9V outputs, 1 500mA 9V output | Switchable voltage: Yes | Weight: 113g
It’s taken a long time for effects pedal power supplies to catch up, but finally, you can power your pedalboard via USB, courtesy of Mission Engineering’s new 529 USB power converter. The supply functions from any USB power cable, as well as a portable USB battery pack, laptop or a car’s USB charging port. Mission sells its own USB battery pack, designed to fit under a Pedaltrain Nano and offering over eight hours of use. Four isolated 150mA 9V outputs are onboard the 529, as well as a high-current 500mA 9V offering. For smaller ’boards, or setups with only one or two high-current devices, it could prove a convenient solution indeed.
10. Mooer Macro Power S8
Ideal if you only need a few isolated outputs
Launch price: $98/£79 | Type: Partly isolated power supply | Isolated outputs: 4 | Outputs: 4 | Switchable voltage: Yes | Weight: 1.12kg | Features: 1 9/12/15/18V DC 200mA output
At a relatively competitive price point, the Mooer Macro Power offers a combination of isolated and non-isolated outputs in a compact package. It has over-current protection, and although there's no specific high-draw output, if you box clever you can simulate one. The non-isolated outs share 400mA combined, so if you connect 4 pedals to the isolated outs, and then a single high-draw pedal to one of the daisy-chained outputs, it should have more than enough power in the 400mA chain to operate.