12AU7 Compressor

The Hagerman Amplification 12AU7 Compressor is an all-analog vacuum-tube compressor designed for transparent dynamic control on guitar or bass. It uses a 12AU7 tube, feed-forward sidechain and custom opto-resistive attenuator to produce soft-knee compression with a 50 ms attack time, providing increased sustain while preserving articulation. The circuit offers up to 22 dB of gain, a 25 Hz–10 kHz bandwidth, 1 Vrms input before clipping and up to 3 Vrms output. The tube operates from an internal 150V supply for high clean headroom. It features true bypass and requires 12V DC center-positive power at 300 mA.