Small pedalboards with 2 or 3 pedals can be supplied with power easily. Especially with analog pedals like a fuzz or a Wah one can simply use batteries.
But if one forgets to pull out the cable after the rehearsal, the batteries will unload pretty fast. And with large pedalboards with 10 or more pedals it makes no sense at all to use batteries for every single pedal.
In this case it is better to use power supplies. But this is where the problem starts: the use of a separate power supply for every single pedal will cause the need of several power-strips to connect all of the pedals. Of course this is pretty inconvenient and needs a lot of space on the board.
Now one can fall back upon the so-called “Daisy-Chain”. This means that several pedals are driven by a single power supply. The 1Spot by Truetone for example is suitable for this kind of power supply.
It is important to make sure that all connected pedals need the same electric current (f. e. 9V) and the same polarity of the mains plug (minus and plus). In addition, the power supply should be able to deliver enough electricity (mA) for all of the pedals.
And you have to be quite careful when you use digital AND analog pedals at the same time. In this case the “Daisy-Chain” with one single cable will lead to undesirable besides noise.
Isolated power supply
In general it is better to use power supplies with isolated outputs. Known providers are, for example, Voodoo Lab, Cioks and, recently, also Strymon. Their products make sure that every pedal is supplied well.
But again it is important that the maximum voltage of a pedal not is exceeded: a 9V pedal should be driven by a maximum voltage of 9V. The amperage (mA) should be appropriate for the needs of the pedal: a pedal that, for example, needs 80 mA should be supplied with 100 mA or even more. Especially digital pedals can take serious damage if they are driven by too little amperage.
Modular power supply
Recently there is some kind of modular power supply. The Gigrig offers several modules, individual suitable for many pedals. By this, one can supply pedals that need a lots of electricity and besides, have a certain input. There is a list where you can find which certain module fits your pedal.
All energized cables of the power supply should be placed far away from the audio-cables. Because it is not always possible to do so, it is quite important that the cables are always crossing right-angled and never are running parallel. In this way interferences will be kept low.
Wah-pedals should also be placed away from the power supply. Otherwise the inductor may captures interferences. The same applies to certain kinds of compressors.