We know you’d rather buy a new guitar pedal. But investing in the best pedal power supply, you can afford will pay big dividends in better sound and greater reliability for years to come.
There was a time when guitar pedals were all powered by 9-volt (9V) batteries. They’re actually an excellent power source – until they die because you forget to unplug the inputs. Battery manufacturers love this feature.
Of course, you can’t use 9V batteries to power pedals that require 12, 15, or 18 volts or AC power. And many new “mini pedals” don’t include a battery connector at all.
Everyone is familiar with the small AC adapters used to power electronic devices, often referred to as “wall wart” power supplies because of their chunky shape. You can buy one of these for each pedal you own, but there are a number of problems with this approach.
First, you’ll need space-hogging AC power strips on your board for all the adapters. Wall warts are bulky (hence the name), taking up even more space. And their weight puts them off-balance, so they can easily become unplugged, usually during your best guitar solo. Finally, some brands use cheap components with little filtering, adding extra noise to your signal.
Therefore, unless you’re using just a couple of pedals for practice at home, a quality power supply is a good idea. But which one offers the best balance of price, features, and quality for you?
So, let’s look more closely at the options you have available as we find the best pedal power supply for your effects board…
Factors To Consider Before Buying
Isolated Power Supplies
Your very first consideration when shopping for a pedalboard power supply is whether you need isolated power. This topic is so important that it bears a deeper discussion.
Perhaps the easiest way to understand isolated power is to consider its opposite, a single battery or wall wart connected to a “daisy-chain” extension cable. The cable connects to the power supply at one end and has several output jacks wired together in parallel. So all the negative (ground) and all the positive leads are connected. It’s a cheap solution, but it can cause problems:
The most maddening of these are ground loops. Power supply outputs that aren’t isolated share a common ground connection, so the ground circuit extends to every pedal. With multiple paths to ground, your board can pick up hum interference from nearby electrical appliances, and even the building’s AC power wiring.
Also, high-frequency noise generated by one pedal, particularly digital devices, can leak into other pedals through the cable. And if one pedal draws significantly more power, the overall output voltage can sag.
With a true isolated power supply, each individual output is separated from the others by a transformer, voltage regulator, opto-isolator, or integrated circuit with an internal LED. Isolated power supplies cost more because they contain additional components, but they solve all the problems we have mentioned.
You’ll seldom find power supplies described this way. Specifications claim they’re “isolated” but are vague about details. In fact, they typically have one voltage regulator for all the outputs of each voltage.
So the 9V and 12V outputs are isolated from each other, but all the 9V outputs are connected together. However, each output has a capacitor to filter out noise and hum.
If you have only analog pedals, or you’re in a non-critical environment, you can probably get by okay without a true isolated supply. But for live performance or studio use, the extra expense is definitely worth the hassles you’ll avoid.
Voltage is the measurement of electrical pressure. Most pedals need 9V power, but not all. Some pedals work with either 9V or 18V, the higher voltage providing extra headroom. Many pedals, for example, the TC Electronic Nova series, require 12V. It’s very important to use the voltage specified by the pedal manufacturer.
Some power supplies provide 9V only. Most have at least one 12V output, and some let you select different voltages for some outputs. A few have low-voltage options that emulate a pedal with a weak battery.
With isolated outputs, it’s possible to use a special Y-cable to connect two of them in series, so the voltages add together. This is an easy way to get an 18V supply.
Make sure the power supply you choose has all the right voltages available. More expensive pedals have several switches to provide a variety of different voltages.
Most pedals require a power supply connector that’s “center-negative.” That is, the inside of the connector is negative (-), or ground, and the outside is positive (+). Pedals have a diagram silk-screened above the power connector indicating the type of polarity required. It’s always wise to check this before connecting them.
Center-negative is the standard protocol for power supply outputs. If you have pedals with center-positive connectors, you’ll need to use reverse polarity adapter cables. Many power supply manufacturers include one or more of these in the package.
Current & Power
Electric current is the rate of flow of an electric charge, measured in amperes (A). Specifically, one ampere equals about 6.4 quintillion electrons per second.
Manufacturers usually specify how much current a particular pedal uses. For pedals that can operate from a 9V battery, the required current is normally less than 70 milliamperes (mA). Larger pedals with LED screens might need 300mA or more.
Conversely, power supplies specify how much current each output can provide. If a pedal tries to draw too much current, the voltage can sag. In the worst case, it can blow a fuse or damage the power supply.
An isolated supply enables you to connect two outputs together in parallel with a special cable to increase the current capacity.
To be precise, electrical devices consume power, which is expressed in watts (W). Power is equal to the electrical pressure available (in volts), times the current flow (in amperes). So a pedal requiring 9V and drawing 200mA uses 1.8W. This is obviously different from an amplifier that uses 200mA at 120V, or 24W.
When comparing power supplies, calculating the power for each output and adding them all together will provide a more accurate measurement of their real maximum output, rather than just looking at current ratings.
For example, four 9V 100mA outputs, two 12V 200mA outputs, and one 18V 100mA output provide a total of 10.2 watts. But don’t worry! We’ve done the math for you.
Other Factors To Consider
Size matters! Pedalboard space is always limited. So a power supply that can be easily mounted out of the way on the underside of the board is a big advantage.
Also, what cables and adapters are provided? You’ll probably get power cables with some of your pedals, but it’s always good to get a full set along with the power supply, plus with a reverse polarity adapter or two and Y-cables to connect two outputs together.
Some pedal supplies work with a wall wart, usually 18V. Others are powered directly from the AC power line. If so, can it accommodate different voltages used around the world? And does it include AC power plug adapters for various standards in different countries?
With all that said, here’s our list of pedal power supplies for you to compare.
Top 8 Best Pedal Power Supply For The Money 2021 Reviews
1 Donner DP-1 Guitar Pedal Power Supply
The Donner DP-1, Joyo JP-02, and Accel FX Source 10M are virtually identical, manufactured in China by one factory for different brands with only cosmetic differences. Significantly, this design does not offer completely isolated outputs.
Each supply requires an input of 18 volts DC. This is supplied by the included “wall wart” adapter, rated at 1 amp (18W). All outputs have separate short-circuit protection and are individually filtered to reduce hum.
There are seven 9V 100mA outputs, plus one each 9V 500mA, 12V 100mA, and 18V 100mA, for a total of 10 outputs and 13.8W. All the 9V outputs connect to the same voltage regulator, so they’re not isolated from each other. The higher current 9V output just has a larger filter capacitor.
For each output, there’s an LED that lights when it’s connected to a pedal. The Donner DP-1 and Joyo JP-02 have blue LEDs, and a switch to turn them off. The Accel FX uses LEDs of different colors and can’t be turned off. However, the power supply has a master on/off switch.
All models include an 18V wall wart adapter that works 100-240V AC, a set of 10 center-positive output cables, and two reverse polarity adapters. The Donner DP-2 model is a heavier-duty option with six 9V 100mA and two 9V 500mA outputs.
The case is all metal and seems sturdy enough for an onstage pedalboard. It’s quite compact, just 5.9 x 2 x 1.2 inches (150 x 50 x 30 mm).
- Inexpensive solution for up to 10 pedals.
- Outputs Individually filtered and short-circuit protected.
- Compact metal case.
- 9-volt outputs not isolated.
2 Mooer Macro Power S8 Effects Power Supplies
The Mooer Macro Power S8 provides a cost-effective and versatile solution when you need a combination of different voltages. It’s powered from the AC power line, switchable between 120V and 240V operation, and protected by a 400mA fuse.
The S8 offers partial isolation and up to 12.6 watts of output power. One isolated output has a switch to select 9, 12, 15, or 18 volts at 200mA. Additionally, there are three 9V 200mA outputs that are individually filtered and surge-protected but not isolated. Finally, four parallel (daisy-chained) 9-volt outputs can deliver up to 400mA total. Blue LEDs indicate active outputs.
Included are four 18-inch (460 mm) and four 24-inch (610 mm) power cables, two polarity adapters, an AC cable to connect to the power line, Velcro strips to tie down all the cables and a small owners manual.
- Variable output 9 – 18V.
- Built-in power supply (no wall wart).
- Not fully isolated.
- Four daisy-chained outputs are subject to noise.
3 T-Rex Engineering FUELTANK-JUNIOR Guitar Effects Pedal
Fuel Tank Junior provides five isolated 9V outputs, each capable of delivering 120mA. It runs off a 115-120V or 230-240V AC power line. The package includes five 20-inch (400 mm) output cables. A T-Rex polarity inverter cable can be ordered separately. You can also power an 18V pedal from two outputs, using an optional T-Rex voltage doubler cable.
It takes up very little pedalboard space, as it’s just 4-1/8 x 3-1/16 x 1-3/8 inches (105 x 78 x 35 mm). T-Rex offers a two-year warranty.
- Individual isolated outputs.
- Small footprint.
- Polarity adapter and voltage doubler cables not included.
- No 12V output.
4 Truetone CS7 1 SPOT PRO
Truetone 1 Spot Pro is a range of high-quality switching power supplies. Their CS7 model provides seven fully isolated outputs, three voltages, and more than 20 watts of power.
Specifically, you get four outputs that can be switched for 9 or 12 volts with a hefty 200mA, two dedicated 9V 400mA outputs, and an 18V 100mA out. Truetone points out that these are only “official” current ratings to satisfy certification agencies. In fact, you can connect a 300mA pedal to a 200mA output with no problems.
The CS7 can easily be used anywhere in the world, as it works with any power line voltage of 100 – 240V.
Included with the CS7 is a full complement of cables: an AC power cord, four 18-inch (457 mm) and four 12-inch (305 mm) power cables, reverse polarity adapters, and even an adapter for older pedals with only a battery clip. Also included are mounting brackets and hardware for attaching the CS7 to a Pedaltrain pedalboard.
- Selectable 9V or 12V outputs.
- Works with any power line voltage.
- Full set of cables included.
- Pedaltrain mounting hardware included.
- Limited to six 9V pedals.
5 MXR M238 Iso-Brick Power Supply
The MXR Iso-Brick is a lightweight power supply that can deliver up to 32W. Its ten fully-isolated DC outputs provide 9 to 18 volts, including two variable outputs. Special noise-reduction circuitry guarantees ultra-quiet operation.
The Iso-Brick provides six 9V outputs (two each at 100mA, 300mA, and 450mA), two 18V outputs at 250mA, and two that can be set from 6 to 15 volts at 250mA. The variable-voltage outputs can be set to 6 volts to emulate the effect of “voltage sag” from weak batteries. Unfortunately, there’s no 9V AC out for pedals like the Digitech Whammy.
Power is provided by an included 18V adapter. Different-colored LEDs indicate good or bad input and output connections, which is a big help in troubleshooting onstage.
The package includes a full set of power cables and AC power plug adapters, but no polarity reverse cables. The Iso-Box is small enough to be mounted on the underside of a pedalboard.
- Ten outputs and 32 watts.
- Isolated outputs with noise reduction.
- Variable voltage outputs.
- No reverse-polarity cables.
6 Mission Engineering Power 529 USB Converter
The Mission Engineering 529 lets you power a pedalboard from a USB connection on your laptop or mobile device, or with a USB wall charger. Its small size – 4-1/2 x 1-3/4 x 1 inches (114 x 44 x 25mm) – allows it to fit comfortably under the smallest pedalboards.
The 529 provides four isolated 9V 150mA outputs for standard pedals, plus one 9V 500mA output for high power devices. It also provides a USB output, allowing two 529s to be daisy-chained for up to ten pedals. This is one of the lowest noise pedal power supplies available.
The package includes a wall power supply, two USB cables, and five power cables. Mission Engineering also makes the 529i USB Power Supply with eight outputs.
- USB convenience.
- Very low noise.
- 9V only.
- Relatively expensive for five outputs.
7 Voodoo Lab Pedal Power 2 Plus Isolated Power Supply
Voodoo Lab makes the Pedal Power line of high-quality and feature-laden pedal power supplies. The 2 PLUS is probably their most popular model, providing about 10W total power. Each of its eight outputs is isolated, short-circuit protected, well filtered, and regulated to ensure reliable operation free of hum and noise.
A block of DIP switches on the bottom of the unit enables each isolated output to operate in two modes. With the switches in the normal position, all outputs are regulated at 9V. Outputs 5 and 6 can supply 250mA for high-current pedals, while the other outputs have 100mA available.
With the switches on, outputs 1 – 4 provide 12.3V at 60mA, while 5 and 6 are unregulated at up to 14.5V for Line 6 devices. Outputs 7 and 8 let you reduce, or “sag” the voltage as low as 4 volts to emulate worn batteries, using controls above the output jacks. It’s musically useful mostly for transistor-based fuzz and distortion circuits.
On the back of the unit is a recessed connector for the AC power cable, plus a courtesy outlet for any device that uses 200W or less. Voodoo Lab makes different models specifically for North America (120V), Japan (100V), and Europe (230V), so you’ll need a transformer to use it in a different region.
With the Pedal Power 2 Plus, you also get six power cables with right-angle connectors and two with straight connectors, a reverse polarity mini plug, a 9V battery snap, and an AC power cord.
- Dual-mode operation for every output.
- Variable voltage sag.
- Very clean power.
- Five-year warranty.
- Different models needed for different line voltages.
- Relatively expensive.
8 Walrus Audio Phoenix 15 120 Volt Output Power Supply
The Phoenix from Walrus Audio is the power supply for serious pedalboards, offering a total of 15 isolated outputs and 21W. Two custom-wound toroidal transformers provide the cleanest power possible.
Available outputs are eight 9V 100mA, four 9V 300mA, two that can be toggled between 9V and 12V, and one that’s switchable between 9V and 18V. The toggle switches on the back of the unit are easy to reach, but there’s a chance you could accidentally flip one.
Phoenix 15 comes with a complete set of 15 power cables, 2 Line 6 adapter cables, and a 5-foot AC power cord. Designed for use in the US, it works with 120V AC only. Its dimensions are 9.75 x 2.6 x 2 inches, and it’s available in black, red, white, teal, and multi-colored.
- 15 isolated outputs.
- Selectable voltage on three outputs.
- 120V AC input only.
- Position of voltage switches not ideal.
Need Some Accessories?
Having a great new power supply won’t be much use without a quality pedalboard, so check out our reviews of the Best Guitar Pedalboards currently available. You might also need some quality patch cables? Find out all about this in our in-depth Best Patch Cables review.
But What Is The Best Pedal Power Supply?
The power supply that’s best for you depends on several personal factors. How many pedals do you have, and what voltages do they require? How much current do they draw? And do you need a power supply that will work in different countries?
Nevertheless, here are our top picks…
Best All-Around Power SupplyTruetone CS7 1 SPOT PRO
This is a solid power supply at a reasonable price, providing six 9V sources, 12V if you need it, plus 18V. All the required cables are included. Universal AC input means it works anywhere in the world automatically. And the Pedaltrain mounting brackets are a nice bonus.
Best High-End Power SupplyVoodoo Lab Pedal Power 2 Plus Isolated Power Supply
It has eight outputs, all the voltage options you’ll need and a five-year warranty. The 2 Plus edges out the Walrus Audio Phoenix 15 because of its much more attractive cost. The only downside is that your American model won’t work in Europe without a voltage converter.
Best Budget Power SupplyDonner DP-1 Guitar Pedal Power Supply
If your funds are tight (because you already bought too many pedals), this is an excellent inexpensive solution. The 9V outputs aren’t isolated, so you might have to come up with creative solutions to deal with ground loops or noise from digital pedals. But in less critical applications, it performs nicely.
Whatever your situation, a clean and reliable source of power makes your board sound better, and your pedals enjoy a longer life. It’s certainly not a glamorous expense, but worth the investment in the long run, even if you have to delay getting that cool new pedal, you can’t live without.