2x LM386N LM386 200 - 700mW Audio Power Amplifier IC 8 PIN DIP
£2.98
The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200. 2x LM386-N Amplifier IC's Supplied.