Intermediate: Variable Bandwidth Filter with Audio Amplifier

For intermediate project builders, this combination variable bandwidth filter and audio amplifier can make your radio listening a lot more manageable and enjoyable. The control at the top adjusts the bandwidth of the filter section, while the control at the bottom is for volume adjustment. Across the back of the board are input jacks for receiver audio and 12V DC, and a small headphone jack for the audio output. Connect a speaker if you'd like. There is plenty of audio to drive one!

Here is how the project looks on paper. On the top of the page is the topical layout using Manhattan-style construction. The red dotted lines are wire jumpers. The circuit schematic is shown at the bottom of the page. By reaching the intermediate level, it is assumed you recognize schematic symbols. There is no parts list - you must follow the schematic and make your own.