What are sags and brownouts?
We’ve probably all experienced the momentary ‘flickering’ of lights when a heavy load such as a vacuum cleaner or amplifier is switched on within our home or studio. The flicker is a result of a short term ‘sag’ in the powerline voltage.
Short duration sags, say between 20 and 40 thousandths of a second often cause no issues as most power supplies have enough stored energy to carry through these events. Longer sags will often result in loss of power, similar to an interruption.
Brownouts are longer events, most typically caused by the power utility ‘stretching’ the power they have available to meet times of high demand.
Linear power supplies, the type most often found in our high performance audio visual systems, are quite susceptible to prolonged low voltage. Power supplies may lose their ability to regulate voltage, causing equipment malfunction and damage. Amplifiers, which typically have unregulated power supplies, will show reduced ability to drive loudspeakers.