Design your own docking station for your MP3 player using this ultra-low cost amplifier board, which can run from either batteries or an inexpensive PSU. The project provides an angle for all interests:

• Product design (1) use conventional resistant materials for the loudspeaker enclosures – just treat the amplifier as a simple plug-in black box;

• Product design (2) – use any one of the vast range of new materials available – concrete, ceramics, plaster, textiles .......

• Graphic design (1) – transform the external look of speaker enclosures by using printed materials

• Graphic design (2) – fabricate the loudspeaker enclosures using folded card methods – e.g., flat pack speakers

• Electronics – build the amplifier using the kit option or design and build one to a different specification

• Science/acoustics – design the enclosure with particular reference to acoustic criteria

Application notes
Any music source that drives a small earpiece is suitable for this project. The amplifier is fitted with a 3.5mm socket so that a standard lead from an MP3 player etc. can simply be plugged in. An external socket can be soldered to the board. Volume is controlled at the player end itself.

Power requirements
The amplifier can be used with a wide range of batteries – e.g., small PP3 (9v) or 4D cells (6v). Batteries capable of supplying higher currents give better sound and less distortion at high volumes: a four AA battery pack is ideal. Any PSU designed for audio applications is also ideal.

Loudspeaker requirements
The amplifier can be used with any size loudspeaker in the 4 – 8 ohm range. The use of lower impedance speakers accentuates base sound - but these are less common. If more base sound is required, one method is to use two 8 ohm loudspeakers connected in parallel for each channel.

Approximate power output:

125mW (RMS) per speaker (8 ohm)
250mW (RMS) per speaker (4 ohm)
(Tested with 9V DC Power)

Also available as a kit of parts that require soldering.

See the impressive range of Docking stations (which use this board) produced by students at Turnford school, Hertfordshire: