A rich, 3-dimensional 500 series tube preamp that can take a flat, uninspiring tone and turn it into a world-class recording. While the Powertube excels on any studio application and instrument, it's performance on male and female vocals is outstanding.

The Radial PowerTube 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 Jensen is legendary for. The signal is then amplified via a select 12AX7 tube using an innovative non-radiating charge pump that supplies 140 volts 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 ideal 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 is equipped with fully variable trim and gain controls. A 10 segment LED bar graph provides visual feedback and driving the PowerTube 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 comes factory-loaded with a select 12AX7 tube along with a second Tonebone distortion pedal tube for more grit and madness.

The Radial PowerTube... the true character of a world class vintage tube preamp without the noise!



Microphone Input Circuit type:100% discrete class A with 12AX7 tube driveMicrophone Input:Transformer coupled, Jensen JT-115KECurrent draw:235mAFrequency response:20Hz ~ 20KHz +0/-1dBInput Impedance:900ΩMic preamp gain:+60dBMaximum gain:+75dB when used with Workhorse*Maximum output:+22dBuOutput impedance:200ΩOutput type:100% discrete Class-A FETCommon mode rejection (CMRR):>84dBEquivalent Input Noise (EIN):-128dBu @ maximum gainDynamic range:>93dBTotal Harmonic Distortion (THD+N):0.05%Intermodulation distortion (IMD)0.011%Instrument Input Omniport input Impedance:150kΩ, unbalanced*Instrument preamp gain:+55dB, unbalanced*Equivalent Input Noise (EIN):-95dBu, unbalanced*Total Harmonic Distortion (THD+N):0.1%Control Panel Meter:10 segment peak indicator with holdPad:VariablePolarity:180°High-pass filter:250Hz cut-off, -3dB at 150HzAir Control:Presence boost @5kHzPhantom power:48VDC - 10mA (as supplied by 500 frame)XLR configuration:AES spec: pin-1 ground, pin-2 (+), pin-3 (-)Ground lift (rear panel):Lifts ground on front panel XLR input onlyMechanical Weight:1.5lbs (0.7Kg)Shipping size:9 x 6.5 x 2 (inches)Compliance (API):YesCompliance (WHOS-Doc):YesWarranty:3 years, transferable

Product Specs

B-Stock (Used)
B-Stock items are sold by an authorized dealer or original builder, but have been opened, blemished, or used in some manner.learn more
Brand Radial
Model R700 0115
Categories 500 Series, Microphone Preamps

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Message Seller

Sound Pure

Durham, NC, United States
Joined: Apr 2013

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Radial Powertube Tube 500-Series Preamplifier Demo/Open Box
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