MegaCube

A spike is a very brief over-voltage 'event' ranging from a few tens of volts above the highest legal peak voltage (360V for 230V), up to several thousand volts. They are typically under 1 millisecond in duration, are very common and often (though not always) the energy involved is small. Longer duration events are called surges and have the potential to do more damage, but mercifully these are less common.

Spikes are caused by things such as lightning strikes, power outages, tripped circuit breakers, fluorescent lights, refrigerators and washing machines switching on and off. The quality and severity of spike activity varies during the day, and from day to day. Even with well-designed equipment, spikes or transients – if regular – can and will prematurely stress and wear out critical mains-connected parts and their insulation.

In our opinion, high voltage spikes can also cause audible degradation of Hi-Fi sound by their effect on a Hi-Fi system's power supply and by raising the background noise level in amplification circuits. The spikes saturate the core of the mains transformer, preventing normal transformer operation during the period of each spike and causing distortion to the waveform. Mains spikes reduce the capacity of the power supply by 'strangling' the transformer operation producing subjective effects on an amplifier like softened bass and increased high frequency distortion.