Isolated Pedal Power Supply using Current Doubler and Voltage Doubler

Does Isolated Power Supplies worth it?

The answer is YES.

The price difference between an fully isolated power supply and a non isolated power supply is very little, yet the benefits are huge.

A quality isolated power supply (for example Vitoos, Voodoo Lab, CIOKS, MXR etc) physically separate the positive (+) and negative (-) lines so a short circuit, in case it happens, will not affect and damage your expensive beloved pedals.

Now days there a a lot of guitar pedals and processors that use digital circuits that turn on and off at really high speeds. The constant switching (ON/OFF) can create what is know as induced electrical noise.This digital components are very sensitive and transfer this electrical noise and show up in your audio as hum or noise.

Here is where the real benefit of an Isolated power supply comes in. Being electrically isolated (having physically separated grounds) limits the possible electrical noise just to the pedal in question. The noise or hum will not pass to all the other pedals connected on the chain.  Imagine having a non isolated power supply or daisy chain. If one pedal's circuit is generating electrical noise that noise will pass to the next pedal and so on. If one of the pedals on your chain is a gain pedal, for example, a booster, this will only increase the noise.

Fully isolated supplies from well know brands, use quality low noise transformers and electrical components. The will usually add other very useful functions such as high current outputs, regulated outputs, and short circuit protection.

Be careful... Many pedal power supplies will claim that they are isolated but they aren't really isolated.

How to know?

To determine is a pedal  power supply you need a bit of technical knowledge and a multi meter. The idea is to find out if all the outputs in the power supply are sharing the same ground(-). You would need to measure continuity between the grounds (-)  among the different outputs.

For example:

After setting the multi meter on the continuity function (resistance (Ohms)) on some meters you would place one of the meters cable on the center terminal of OUTPUT 1 and the other meters cable on the center terminal of OUTPUT 2.  If the meter shows infinite resistance or if it doesn't beep, then it means that they are not physically connected. In other words they are not sharing the ground (-) circuit.

Price is sometimes a clue. If they are selling for less than $60, it is very unlikely that they are fully isolated. Usually above $60 you start to see a few fully isolated supplies

Does an Isolated Power Supply guarantees zero noise?

The answer is NO.

Having a fully isolated power supply makes a huge difference and for sure it will not generate noise itself and will not transfer electronic noise (in case you have a noisy pedal) through your pedal line. It will yield a clean audio signal if and only if:

- The pedals you are connecting to the supply are not noisy. Usually digital effects a more sensitive and tend to create noise.

- The  electrical outlet (wall outlet in your home or studio) where you are plugin in the power supply is correctly grounded. You see, sometimes electrical wiring in buildings are not correctly grounded, so if for example, an electrical device as a refrigerator, TV, computer, etc is creating electrical noise/hum and you are sharing the same electrical (for example you are in the same house) even if you are using a high quality professional grade isolated power supply, that noise/hum can get into your power supply and thus your audio signal. Is it the power supplies fault? No.

Hacks and tips when using an Isolated Power Supply

With a quality power supply and the right cables you can extend the variety of effect pedals and processor that you can use.

Doubling Current:

Doubling Voltage:

Changing Polarity: