| 摘要 |
PURPOSE:To prevent sound leakage by directly detecting a signal level of a medium and a high sound frequency as to an input signal of an earphone and suppressing the signal level based on the result of detection. CONSTITUTION:While contacts a, c of a slide switch 36 are short-circuited, an input signal of earphones 28, 30 is fed back to a tape recorder main body 2 via resistors 32, 34. When the slide switch 36 is thrown to the positions of contacts b, e, transistors (TRs) 64, 66 are controlled in response to the feedback quantity depending on the resistors 32, 34, 38 and the sound volume of the earphones 28, 30 is suppressed in response to medium and high sounds of the reproduction signal. Furthermore, when the slide switch 36 is thrown to the positions of contacts a, c, the input signal of the earphones 28, 30 is fed back by a feedback quantity depending on the resistors 32, 34 and then the sound volume of the earphones 28, 30 is suppressed further in comparison with the case of selecting the contacts b, e. Thus, the sound quality deterioration is effectively avoided to prevent sound leakage. |
