Anyway the first two cases give good results because the voltage was right, the polarity was right and your supply provided enough current to power the pedal. The second case wasn’t so pleasant because the supply wasn’t filtered and regulated enough, so you got a lot of noise (broom, hiss etc). The third case was bad – the pedal is broken and needs to be serviced or replaced. Most probably you used an AC supply, but the pedal needed DC.
So my advice – read the labels and use only power supplies that are made for powering guitar pedals like our Juice power supply units.
We all came across a noisy pedal, didn’t we? In most cases high gain fuzz pedals, modulation pedals can produce LFO tics and clicks although the pedal is bypassed. This often occurs when all the pedals are connected to a common ground. The solution for hum and noise elimination is to use an insulated power supply. Power your “noisy” pedals with one isolated section, and all the other effect to other sections – this way you’ll break the ground path and in most cases the hum will disappear. This is the main advantage of our Juice Deluxe Power Supply.
We’ll talk about power supply specifications in this article. Let’s start with current specifications. To get the pedal running you have to apply voltage to it. The pedal will consume the needed current to work. That means that your power supply should be capable of providing at least as much current as the pedal needs (the more the better). Most of analog drive and boost pedals consume 10-20 mA, so if you’re power supply provides 500 mA, that means it can drive 25-50 pedals. Digital pedals usually consume a lot more current, so be aware of that when using those. The maximum power supply current should be always higher (or at least the same) as the current consumed by your pedals.
Voltage? Most of the pedals on the market run on 9 VDC. When the first overdrive and fuzz pedals were made, there were no power supplies to power pedals. Only batteries, 9-volt batteries that is. Throughout the years this voltage level became an unwritten standard for powering guitar pedals. There’s also a lot of effects that need other voltages, but most of the present pedals run on 9 Vdc (center negative). There’s only one rule when it comes to powering your pedals: Power them the way they should be powered. Although most overdrive pedals work better when powered at higher voltages, don’t do it if you’re not 100 % sure that it won’t do any harm to the pedal. Stick to the documentation or contact the manufacturer for more information on powering your pedal.
Polarity? The center-negative polarity is also a thing that became an unwritten standard throughout the years. Most of early pedalbuilding companies (such as Boss or Ibanez) were using this polarity in their products. The “center-negative” supply means, that the center pin of the power connector is grounded, and the outer pin is connected to positive. If you connect the effect the other way around, you can damage the circuit inside your pedal. All of our pedals have an integrated polarity protection diode, so you the pedal won’t be harmed if plugged into the wrong supply for a short time.