The audio amplifier that makes up the stereo is a Klipsch ProMedia 2.1 unit. Originally intended for use as high-end computer speakers, the one used here was my own set used steadily from 2003 - 2013. Still going strong, it now lives on as the muscle of this machine.
With a peak output of 200 watts, with a sustained 55 watts per channel, the amplifier powers an 8" subwoofer two channels of 3 speakers each. Each side has two mid-range drivers and a crossover splitting out to a high frequency tweeter.
The audio signals from the record player, Raspberry Pi, and auxiliary RCA input all run through the input selector, a rotary switch. After the audio signal runs through whichever input is selected, it passes through the output switch (going either to an external stereo or the internal amp), through the equalizer, then finally conclude at the amplifier.
The record player also runs through a pre-amp before it reaches the selector switch, which is necessary when using modern amplifiers that don't contain a specific phono input.