In a television receiver apparatus is provided for muting an audio power amplifier having continuous operating supply voltage applied thereto from a standby power supply even when the receiver is in an "off" condition so that spurious noise and hum coupled to the power amplifier will not be amplified...http://www.google.de/patents/US5029005?utm_source=gb-gplus-sharePatent US5029005 - Apparatus for the muting of an audio power amplifier in a standby mode
