| 摘要 |
PURPOSE:To easily adjust a bias current by using one-terminal sides of a right and a left sound recording and playback head as a common terminal, providing a common- terminal side bias oscillation flow-in source, and connecting a playback amplifying circuit equipped with a playback control signal circuit and a sound recording signal control circuit to other-terminal sides. CONSTITUTION:When the tape recorder is in playback operation, an electronic switching circuit 9 turns on to hold the common terminal of sound recording and playback heads 1 at the earth potential, and other-terminal sides are coupled with the playback amplifying circuit 3 controlled into an operation state through an electronic switching circuit 13 to perform amplification. The output of a sound recording equalizer 6 is not fed back to the sound recording and playback heads 11 because electronic switching circuits 14 and 10 are off. When microphone sound recording is performed, the sound recording equalizer 6 is connected to one-terminal sides of the sound recording and playback heads 1 and the right and left common terminals of the sound recording and playback heads 1 are applied with a bias oscillation output because the electronic switching circuit 9 is applied with no bias. Therefore, a sound recording current flows through the secondary side of the oscillation coil of a bias oscillation circuit 7. |
