A BK Butler Tube Driver guitar effects pedal in a rectangular steel enclosure, with a row of rotary knobs across the top panel, two small LED indicators, and a footswitch at the front.

BK Butler Tube Driver w/ Bias Knob - 2018

$321.95
$321.95
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A BK Butler Tube Driver guitar effects pedal in a rectangular steel enclosure, with a row of rotary knobs across the top panel, two small LED indicators, and a footswitch at the front.
  • A BK Butler Tube Driver guitar effects pedal in a rectangular steel enclosure, with a row of rotary knobs across the top panel, two small LED indicators, and a footswitch at the front.
  • A BK Butler Tube Driver guitar effects pedal in a rectangular steel enclosure, with a row of rotary knobs across the top panel, two small LED indicators, and a footswitch at the front.
BK Butler Tube Driver w/ Bias Knob - 2018

BK Butler Tube Driver w/ Bias Knob - 2018

The BK Butler Tube Driver is a hand-built analog overdrive/boost pedal that runs the guitar signal through a 12AX7 vacuum tube in a starved-plate configuration.

$321.95
$321.95
Condition Very Good
Specs Verified model facts
Use Players who want a real 12AX7 tube overdrive/boost with fine control over feel and gain.
In stock Ask a question

Specifications

Analog tube overdrive · 120V AC mains, attached cord

Identification

Brand BK Butler
Model Tube Driver - 5 Knob Bias
Pedal Type Analog tube overdrive
Build Hand made

Tube & Circuit

Preamp Tube 12AX7 vacuum tube
Tube Configuration Starved-plate
Signal Path Op-amp + 12AX7 + passive EQ
Bias Control Function Adjusts tube cathode current

Controls & Indicators

Output Level Output Level
EQ Hi EQ Hi (passive)
EQ Low EQ Low (passive)
Tube Drive Tube Drive
Bias Bias (5th knob)
Footswitch Engage/bypass footswitch
LED Indicators Green power LED, red engage LED

Power

Power Source 120V AC mains, attached cord
Export Voltage Option 220-240V 50/60Hz option
Power Compatibility Wall outlet, three-prong cord; no Boss-style plug

Physical

Dimensions 7.25 in L x 4 in W x 3.5 in D
Weight 2.5 lb
Housing Steel enclosure
Connectors Input & output jacks, rear power cord

Warranty

Manufacturer Warranty 3-year warranty (new)

Fit and constraints

Players who want a real 12AX7 tube overdrive/bo… · 120V AC mains, attached cord

Intended use

Use Players who want a real 12AX7 tube overdrive/boost with fine control over feel and gain. The 5-knob Bias version is best for tone-tweakers who like to dial in the tube's response without physically swapping tubes, and for anyone chasing the classic Tube Driver overdrive voicing. The two-band Hi/Low EQ suits players who want to shape the overdrive to a specific pickup and amp pairing.
Not for Anyone building a compact, battery- or 9V-powered pedalboard: this pedal plugs into a 120V AC wall outlet via an attached mains cord and won't run from a pedalboard power supply or daisy chain. It is also large (about 7.25 x 4 x 3.5 in) and heavy (2.5 lb) for a single overdrive, so skip it if board space or weight is tight. Buyers who require true-bypass switching should confirm it with the seller, since it isn't specified.

Constraints

Power120V AC mains, attached cord
ControlsPower is the main gotcha: it draws from 120V AC mains through a fixed three-prong cord ...

To use it

Description

Product details

The BK Butler Tube Driver is a hand-built analog overdrive/boost pedal that runs the guitar signal through a 12AX7 vacuum tube in a starved-plate configuration. This unit is the five-knob "Bias" version, which adds a fifth control that adjusts the current applied to the tube's cathode, letting the player vary gain, texture and dynamics without swapping tubes. The standard controls are Output Level, a two-band EQ (Hi and Low) and Tube Drive, plus a footswitch and two LED indicators for power and engagement. It is powered directly from 120V AC mains through an attached three-prong power cord rather than a standard pedalboard power supply.

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