The BA3420AL is dual recording/playback preamplifier for radio cassette players. It has an internal switch for switching between playback head, mic, and radio input modes, and also includes a bias oscillator and regulated voltage source for radio use.
All control is possible with one external switch, allowing designers to reduce the number of external components and the size of their set designs.

Features
1) Internal three-mode input/output switch for playback head, mic and radio modes.
2) Built-in bias oscillator and regulated voltage source for radio use.
3) Control of the internal switch and regulated voltage source is possible with one external switch.
4) Low distortion.
5) Low noise.

Applications
    Radio cassette recorders