View tda7335 datasheet:

TDA7335 ® STEREO PREAMP + AMS + DOLBY B* NOISE REDUCTION PROCESSOR DUAL CHANNEL PROCESSOR FOR PLAY- BACK APPLICATIONS. STEREO DOLBY B NR SYSTEM LOW NOISE HEAD PREAMPLIFIER MUTE, AUTOREVERSE, AMS (AUDIO MU- SIC SENSOR) FUNCTIONS INTERNAL SWITCHES FOR EQUALIZATION DOLBY REFERENCE LEVEL -6dBm (388.2mVRMS) MINIMUM NUMBER OF EXTERNAL COMPO- NENTS SDIP30 LOW SUPPLY CURRENT (18mA) MIXED BIPOLAR/CMOS TECHNOLOGY ORDERING NUMBER: TDA7335 DESCRIPTION The TDA7335 is a monolithic BICmos IC de- signed for use in stereo cassette player systems. PIN CONNECTION (Top view) The device includes two separate audio channels composed by low noise preamplifier, Dolby B noise reduction system and Audio Music Sensor. The dual preamplifier contains mute, autoreverse, metal/normal facilitie