QRPBuilder Audio Amplifier kit – $20
The QRPBuilder Audio Amplifier is a versatile through hole amplifier kit for projects that use earbuds or headphones that need some extra amplification, or to drive a speaker. It can be configured as a desktop or internal mounted option at a much smaller footprint. It is jumper selectable for 20X or 200X native amplification and also has an onboard volume control. Input and output is via separate 3.5mm jacks. It is easy on power (5mA) and powered on board using a 9V battery (not supplied) that lasts many hours or cutting on the dotted line will remove the battery, power switch, and led resulting in a board half the size for mounting internally, using pads for connecting external input, output, and power for mounting inside your project enclosure. The size with the battery option measures 2 3/4″ x 2 1/4″ and the internal option is 1 1/8″ x 2 3/4″.
The tools required are a soldering iron with a small tip, rosin core solder, small side cutters, and can be built in an hour, depending on your experience. On a difficulty scale of 1 to 5, 5 being the most difficult, this is rated at 2.
For support email to: qrpbuilder@gmail.com
Click here for the assembly manual.