High-quality amplifier with microphone mixing function. Power-on tested only. To be treated as a junk item. Received from an acquaintance. While this is speculation, I believe it was purchased about 50 years ago, used until around 2000, and then left unused. - Model: MA-10A - Function: Microphone mixing amplifier - Power switch: ON/OFF - Mixing level adjustment: Variable - Input sources: Microphone, Tape, Source Thank you for viewing.