Audiolab DCBLOCKBK Audio Grade Mains Filter & Direct Current Blocker - BlackDC BLOCK The DC Block has been designed to improve the quality of AC electricity that feeds our audio and AV systems. Mains electricity has a fundamental influence on the audio signal as it passes through a system,from source to amp to speakers. The mains supply in a typical dwelling is subject to interference induced by a range of issues,causing the AC waveform to distort before it reaches each component. This creates noise in the audio signal,which