Non-isolated power supplies for guitar pedals are basically one power source that a number of different pedals can draw from, often in “daisy-chain” fashion. In most cases, this works fine. However, more pedals pulling power from the same source increases the capacitive load on the power supply, which can result in one or more pedals being noisier than usual, depending on the pedals in use. In these situations, an isolated power supply — where each output on the power supply is completely separate and isolated from the others — might be just what the doctor ordered. By isolating each output, an isolated power supply lowers the capacitive load on the power rails, which should reduce the noise level of pedals that are noisier with a non-isolated power supply.