Any discussion of pedal power supplies has to come with the caveat that they’re not the shiniest or funniest thing you can buy for your rig. Nevertheless, apart from a good Distortion, delay and guitar tunerthis is the most important purchase you can make for a crankset.
No crowd will ever notice the difference between the subtle flavors of overdrive, or a modern amp simulation and the real thing, but they’ll notice ground hum and signal noise. Also, they will definitely notice your rig shutting down due to a dead battery.
With that in mind, we’ve compiled nine compelling arguments for why a bottom bracket power supply should be next on your hit list. If you decide to take the plunge, you’ll also find shopping tips further down the page.
1. It’s more “pro”
Sometimes having neat and tidy gear can be inspirational in itself. Having a brick on the underside of an aluminum rack panel with proper IEC looks tidy, looks neat, and changes the “feel” of your setup. This means that it will probably also affect the way you play.
2. It’s quieter
Since we’re only talking about isolated power supplies here, we can assume you’re upgrading from batteries or a cheaper daisy chain. Now technically it might not be quieter than discrete 9V batteries, but it will be quieter than using a cheap wall wart or daisy chain power supply. When we finally purchased an isolated power supply, we were amazed at the difference. It turned out that our practice space had poor wiring, and the isolated power supply drastically reduced background noise.
3. You can use different voltages
Compared to both a battery and a cheap power supply, most decent isolated power supplies will have at least one variable voltage output. If you have overdrives that can be run at higher headroom using higher voltage, these are ideal for getting the most out of your drives.
4. There are no batteries to run out of
Besides the environmental impact of using the batteries, there is also the hassle of changing them. Granted, on a Boss-style pedal, it’s pretty easy and doesn’t involve removing the pedal from your board. However, for most boutique style pedals in Hammond cases, you must remove the pedal from your board and remove the back to change a battery. More than the hassle, there’s the risk of a dead battery damaging your entire board. For most true-bypass pedals this is unlikely to be a problem, but buffered pedals can often transmit no sound if not powered.
5. A higher amp supply
If you use a cheap power supply or daisy chain it will have a limited amount of current it can supply. Let’s say it’s 500mA. That’s enough for a few pedals, but add complicated digital delays and even if you daisy chain the current draw will become too much. Some very large units can draw up to 1A, but this is very rare.
The advantage of an isolated power supply is therefore not only noise reduction, but the fact that each discrete port can supply up to its maximum rated power consumption without any problems. Some power supplies are designed in such a way that they can route any unused draw to high-efficiency outlets that draw more, which is the case on the Truetone CS-12. This is useful if you have, say, an old-school Whammy. As long as there is enough excess capacity, the CS-12 will happily supply the monster 1.3A that the pedal draws!
6. Ergonomics and portability
Compared to a daisy chain connection, the order of having a single IEC cable and a brick firmly anchored under a board has another advantage: better ergonomics. The board is easier to use, easier to move and faster to set up. Back when we had two wall warts, we had to find two outlets on site, and while this seems like a very minor issue, it’s certainly easier to just switch, plug in one outlet and go.
7. You may not have a choice
Simply put, many modern pedals for space or other reasons don’t even have a battery clip anymore. So-called “micro” pedals almost without exception require a power supply to use them. Many boutique pedals choose to use the space that would be taken up by a battery pack to cram in more circuitry.
8. It’s easier to grow
If you get a larger PSU that supports 6, 8, or even 10 or more pedals, that means no matter how many pedals you currently have, you have room to flex up to the number maximum number of pedals supported by the power supply. As a result, some of those larger supplies that cost more than the cost of a pedal start to make more sense, because you buy it once and it will grow with you for a decade.
9. It gives you a limit
The reverse is also true – if you have a power supply that will run, say, ten pedals, that gives you a useful creative limit to work with. At one point we used two boards, totaling 25 pedals, but a new power supply forced us to rethink, bringing it down to ten pedals on a Pedaltrain JR. Since then, this chart has remained unchanged for almost four years – unlike the weekly hashes and changes that occurred before.
What to look for in a diet
There are three things you need to be aware of when choosing a power supply. The most important, whether isolated or not. Second, how many ports it has. Third, how many amps or milliamps of current the ports can deliver.
Isolated simply means that each output is isolated from each other. It’s like giving each pedal its own power directly to the wall. Better, because the insulation uses a transformer, it also provides noise decoupling from the wall. Without an isolated power supply, a noisy pedal can spread power line noise to all of the pedals on your board. Although there is a price difference, non-isolated power supplies are not worth using. Isolated power supplies can’t eliminate all sources of noise, but they do cover the major bases of stable, consistent sound. They also tend to be higher quality, which means they don’t introduce power line noise.
The ports and amp or milliamp supply are pretty simple. More ports mean more pedals. Current draw is interesting, as many pedals draw very little, but complex digital delays and anything with a screen draws much more. This is why a cheap power supply may not be able to drive many digital delays. An isolated power supply with multiple 500mA outputs won’t even flicker.
Some power supplies also have additional features, like daisy chaining, IEC outputs, or a variable voltage port to mimic a dying battery. Unless you have a very specific need, most of these “power user” features are unlikely to sway your decision. The only feature that might be having a dedicated 9V AC output, which is useful for running older Digitech products like the Timebender, Whammy IV and below, and other weird 90s units like the Station space XP-300.
The last thing to consider is that although 9V DC, center negative is the de facto standard for pedals, some are 12V or 18V. In reality, most of them will run on 9V, but it’s always worth consulting the manual. Many power supplies have a few outputs that can be switched up to 12, 15, or 18 volts to accommodate this.