Transformers come in many shapes and sizes, and are designed for many different purposes. One unique function we use in the audio industry is the isolation properties of a transformer. All transformers provide electrical isolation between the primary and secondary windings. This means that the signal connected to the input side is not physically or electrically connected to the output side. When a signal enters a transformer, a magnetic field is created that ‘induces’ a signal into the output side. Because there is no electrical connection between the input and output they can be effectively used to prevent ground loops and other problems that occur when equipment gets connected together. Most transformers are used to either step a voltage up or down, balance an unbalanced signal (or vice versa, or to provide several different voltages from one input (such as in a power supply). These all provide the same isolation as an isolation transformer. What makes an isolation transformer unique is it is designed with only that purpose in mind. That means the output voltage (or signal) is always the same as the input signal. They are used when you don’t want to change your signal, only isolate the components.