The following circuit diagram is designed to be used as an amplifier (including loudspeaker, batteries, input and output jacks) which is fitted into a packet of cigarettes or Fuzz-box. This small amplifier was intended to be used in conjunction with an electric guitar to do some low power monitoring, mainly for practice, either via an incorporated small loudspeaker or headphones.
According to the designer (RedCircuits.com) this amplifier can be used in three different ways: Loudspeaker amplifier; Headphone amplifier or low power loudspeaker amplifier; and Fuzz-box. This amplifier consists of following parts: resistor, electrolytic capacitor, polyester ceramic capacitor, electrolytic capacitor, audio power amplifier IC, stereo jack sockets (switch), loudspeaker, PP3 battery or AAA battery.
Find more information about Circuit Diagram for Mini Portable Guitar Amplifier here – source: RedCircuits.com