Patent ID: 8054998
Filing Date: 2011-11-08
Classification: H04R

Abstract:
1. A multichannel amplifier comprising: a first input terminal to which a front channel signal is inputted; a second input terminal to which a surround channel signal is inputted; a first volume control unit to which the front channel signal is inputted and which controls level of the front channel signal; a second volume control unit to which the front channel signal or the surround channel signal is inputted and which controls level of the front channel signal or the surround channel signal; a first amplifying unit connected to the first volume control unit, amplifying the front channel signal supplied from the first volume control unit, and outputting the amplified front channel signal to a front speaker; a second amplifying unit connected to the second volume control unit, amplifying the surround channel signal supplied from the second volume control unit, and outputting the amplified surround channel signal to a surround speaker; a third amplifying unit connected to the second volume control unit in parallel with the second amplifying unit and amplifying the front channel signal supplied from the second volume control unit; a headphone output terminal to which a headphone can be connected and from which the front channel signal supplied from the third amplifying unit is outputted; a first switch unit for switching a first path extending from the first input terminal to the front speaker via the first volume control unit and the first amplifying unit to a connection state or a non-connection state; a second switch unit for switching a second path extending from the first input terminal to the second volume control unit to the connection state or the non-connection state; a third switch unit for switching a third path extending from the second input terminal to the second volume control unit to the connection state or the non-connection state; a fourth switch unit for switching a fourth path extending from the second volume control unit to the surround speaker via the second amplifying unit to the connection state or the non-connection state; a fifth switch unit for switching a fifth path extending from the second volume control unit to the headphone output terminal via the third amplifying unit to the connection state or the non-connection state; and a control unit for controlling switching between the connection state and the non-connection state of the first to fifth paths based on whether the headphone is connected to the headphone output terminal or not, wherein when the headphone is not connected to the headphone output terminal, the control unit controls the first and second switch units so that the first path is in the connection state and the second path is in the non-connection state.