World's Smallest Fully Self-Contained 20 Watt Class AB Power Amplifier

Length is a little over 5 1/8th inches

This is a stereo 30 watt class AB amplifier that uses a large scale IC as its main amplifier.  This tiny unit can be driven by an iPod or other music player, or a PC's autio output.  The volume and tome can be controlled by an external tone control such as the Velleman Volume and Tone Control Preamplifier Kit K8084, K100 - Stereo Pre Amplifier With Tone Control Kit, or equivelant, or by the music player.  It does have a preamp.

Note.  This is not a class T or D switching amp.

Right out Input Left out


Velleman K4003 Kit

The basic building block of this amplifier is the Velleman k4003 amplifier module kit which is primarily made up of one 2 channel TDA2616 IC.


Internal from top Side view

Side view

Two thirds of the internal box is a shielded iron core 24 volt transformer.

The main board has been set vertically sideways to the IC allowing it to fit into the remaining narrower space. The IC leads were extended to connect to the board. The main filter capacitor leads were also lengthened and they were mounted onto the two binding posts.

K4003 Schematic


Board Assembly Instructions

Board Layout


  • TDA2616 IC amplifier
  • music power output: 2 x 30W / 4ohm
  • RMS output: 2 x 15Wrms / 4ohm or 2 x 10Wrms / 8ohm
  • total harmonic distortion: 0.07% (1W / 1kHz)
  • channel separation: 70dB
  • frequency response: 7Hz to 60kHz (-3dB)
  • signal-to-noise ratio: 98dB (A weighted)
  • input sensitivity: 300mV / 150Kohm
  • transient suppression
  • overload and short-circuit protection: max. 1h
  • 1 input 1/8th inch stereo jack (tip left, ring right)
  • 2 output 1/8th inch left and right mono jacks
  • front mounted power switch
  • neon pilot light
  • 24v ct 2A internal shielded power transformer
  • 117 Volts @ .25A
  • 3 1/4 wide X 2 1/4 height X 5 3/16 depth[1]
  • total weight: 2 lbs. 7 oz.

[1] Includes heat sink but does not including front power switch