Active Speaker

It would obviously possible to buy an Active Speaker for a homebrew amateur radio station, and probably cheaper, but in order to reach my goal of a 100% homebrew station, I need to think about building a speaker.

I came to the conclusion this should be either active or passive (switchable) and an audio filter should be incorporated in order to narrow the audio bandwidth.  This will make the speaker more useful than a purely a speaker in a box.

The loudspeaker itself was a fortunate opportunity.  While at the Ham Radio Exhibition in Friedrichshafen last year, I was able to pick up a very good rectangular speaker for just one Euro.  Finding a box that the speaker would fit in was no problem - Conrad has an ABS box of approximately the correct size.

The box was then drilled to accomodate the relevant parts.  These are two potentiometers (one for the volume, and one for the filter bandwidth), an LED to indicate that power is present for the active parts, a switch to switch between passive and active and of course two input jacks - one for power, and one for the audio input signal.

ABS has advantages and disadvantages over metal!  It is obviously somewhat easier to drill being softer, but the drill seems to run much easier than it does with metal.  Fortunately, I was able to get all of the necessary holes drilled with reasonable accuracy.

Once all of the holes were drilled, the components were placed in the box.  The circuit itself is still a work in progress.