pocket amplifier project

general information

The goal of the project was to build a pocket-sized audio amplifier for headphones or computer speakers. The entire cost of the project was minimal since the casing was made from an Altoids can and many of the resistors required were already on hand. However, some parts needed to be purchased. The OPA2132A-ND dual FET opamp was $5.40, the polypropylene 0.1 microfarad capacitors (2) were $0.86 each, and the stereo 3.5mm jack SMD connectors (2) were $0.63 each. All were obtained from Digikey. Also, the potentiometer used also as a power switch was $5.44 from RS Components. Conclusions: The amplifier works very well. Sound is greatly amplified. Possible improvements would be to obtain a logrithmic potentiometer for volume control as opposed to linear. The linear does not work well for the logrithmic nature of the audio. Also, the placement of the potentiometer is much too close to the input and output connectors. The pot is nearly impossible to turn with both cables plugged in. A more creative casing and layout could resolve this issue and make the device more compact.

reports and documentation

Parts Layout
Parts List
Opamp Datasheet
Potentiometer Datasheet
Stereo Plug Datasheet
CMOY Pocket Amplifier Origianl Project Page