Patent ID: 9413304
Filing Date: 2016-08-09
CPC Classification: H03F

Claim Text:
1. An electronic device comprising: an amplifier which is configured to amplify a sound signal and comprises a vacuum tube comprising a heater configured to emit heat to heat the vacuum tube; a voltage supply which is configured to supply a first voltage and a second voltage which is higher than the first voltage; and a controller which is configured to control the voltage supply to supply the second voltage to the heater in response to supply of a drive voltage to the amplifier being started and control the voltage supply to supply the first voltage to the heater in response to a temperature of the vacuum tube reaching a predetermined temperature, wherein the vacuum tube comprises a temperature sensor configured to sense the temperature of the vacuum tube, and wherein the controller controls the voltage supply to supply the first voltage or the second voltage to the heater based on the temperature of the vacuum tube sensed by the temperature sensor.