The Radial Engineering PowerTube Preamplifier is an old-school, 100%, discrete, class-A vacuum tube microphone amplifier, intended to capture the essence of the voice or instrument while adding the rich harmonics, warmth, and character of a transformer-coupled tube circuit.
Designed to fit inside the Radial Workhorse and other 500 series racks, the single-wide PowerTube begins with an ultra low-noise Jensen input transformer. This exhibits near-perfect frequency response while producing the warm Bessel curve that is characteristic of a Jensen transformer. The signal is then amplified via a select 12AX7 tube using an innovative, non-radiating charge pump that supplies 140V to the tube to deliver the excitement and character of a high-voltage vintage tube amplifier. This feeds a class-A, balanced output stage that together can produce as much as 60dB of gain. This makes the PowerTube suitable for use with all microphones.
Features include an easy-access front-panel XLR input with a safely recessed 48V phantom power switch. To optimize signal-to-noise, the PowerTube Preamplifier is equipped with fully variable trim and gain controls. A 10-segment LED bar graph provides visual feedback. Driving the PowerTube Preamplifier into the red is encouraged. This increases the grit, harmonic content, and distortion. For even more character, activating the air adds a slight edge to a male vocal or sparkle on an acoustic guitar. Low-frequency resonance is easily tamed using the high-pass filter. For added pleasure, the PowerTube Preamplifier comes factory-loaded with a select 12AX7 tube along with a second Tonebone distortion pedal tube for more grit and madness.