The exact effect of noise is dependent on the quality of the power supply inside your equipment, but unfortunately there is no relationship between equipment price and power supply performance!

Noise is created by a large number of things, including radio frequency interference (RFI), electro-magnetic interference (EMI), computer and switch mode power supplies, lighting dimmers and appliances.

Small levels of noise can result in degradation of sound and picture whilst larger levels sometimes manifest as audible pops, clicks and visual ‘snow’.