12AX7 Overdriver

The Hagerman Amplification 12AX7 Overdriver is an all-analog vacuum-tube overdrive built around a 12AX7 tube and designed to produce preamp-style saturation. Its internal biasing is similar to a cold-clipper stage, allowing the circuit to generate overdrive from its own gain and respond to additional boost from pedals placed before it. The circuit provides up to 40 dB of gain, a 30 Hz–5 kHz bandwidth and 470 kΩ input impedance, with clipping beginning at approximately 30 mV input and a maximum output of 2.5 Vrms. The tube operates from an internal 160V supply. It features true bypass and requires 12V DC center-positive power at 330 mA.