Mini Portable Guitar Amplifier CircuitThis mini amplifier was meant to be used in conjunction with an electric guitar to do some monitoring of low consumption, mainly for practice, either through a small speaker or headphones. The complete circuit, speaker, batteries, input and output can be locked in a small box the size of a pack of cigarettes, or can also be installed in a real pack of cigarettes, as some units and made available on the market .
This design can be used in three ways:
- Loudspeaker amplifier: when powered by a 9V alkaline battery it can deliver about 1.5W peak output power to the incorporated loudspeaker.
- Headphone amplifier or low power loudspeaker amplifier: when powered by a 3V battery (2x1.5V cells) it can drive any headphone set type at a satisfactory output power level or deliver to the incorporated loudspeaker about 60mW of output power. This configuration is useful for saving battery costs.
- Fuzz-box: when powered by a 3V battery (2x1.5V cells) and having its output connected to a guitar amplifier input the circuit will behave as a good Fuzz-box, showing an output square wave with marked rounded corners, typical of valve-circuits output when driven into saturation.
