When designing a superheterodyne receiver, terminating mixers properly is important. This is especially important for the second mixer which is responsible for converting the intermediate frequency (IF) into audio. Even at this stage of the circuit, maintaining a consistent 50 Ω termination across all frequencies is required to minimizing distortion products and maintain a high dynamic range.

I recently purchased a Roland Rubix22 USB audio interface second-hand for my PC, and being that it has XLR and 1/4 inch mic jacks, I thought it would be fun to have my hand at making a microphone. While looking into the different types of microphones that exist, I chose to try making a ribbon mic.

At my PC I usually use headphones and an FX-Audio DAC to listen to audio, but occasionally I will hook up my JBL partybox to play music with a speaker. The issue I was having was that the line level output from the DAC was at a fixed volume. So as a small, simple, 1 hour project, I made a stereo volume knob for the line level output.