The Colombo Audio Electronics Pulse Driver is a fully customizable overdrive from Italy, inspired by the sound of the 1983 B.K. Butler design. What makes it unusual is that it chases that tube sound without a tube: Delicious Audio's Paolo De Gregorio describes it as a pedal that "recreates that 12AX7 tube design without an actual tube," using solid-state stages to recreate the sound of the original circuit1. It sits in the broader family of overdrive pedals that trace their lineage back to the Tube Driver.
A solid-state take on the Tube Driver
The Pulse Driver draws heavily on the Chandler / B.K. Butler Tube Driver. As Delicious Audio puts it, "the Tube Driver reincarnates much of the circuitry, solving the defects" of the original design1. The original is a tube-driven overdrive circuit, and the Pulse Driver's approach is to model its behavior with solid-state components instead, which means no tube to replace and no tube-related maintenance for a player to deal with.
In its 12AX7 mode, the pedal is characterized by a very high gain and very pronounced mid frequencies, which Delicious Audio describes as perfect for strongly distorted and aggressive sounds1. Players looking at how this kind of circuit compares with other drive approaches can see the Boss SD-1 vs Ibanez TS9 Tube Screamer comparison for a different overdrive lineage.
Three tube modes and the output control
The pedal's central feature is a set of solid-state stages that can recreate the response of three different tube types1:
- 12AX7: the high-gain, mid-forward mode described above
- 12AU7: a lower-gain tube type
- 12AT7: another distinct tube response
For output level, the pedal has a Volume control: "Volume: controls the signal output level"1.
Power
The Pulse Driver works with a standard 9Vdc power supply (center negative) and can accept a voltage up to 18Vdc, which Delicious Audio recommends for obtaining the pedal's full character. It draws about 8mA, and there is no battery power supply1.
The pedal has no battery option, so it needs a center-negative power supply on the board. It draws only about 8mA, so it is light on a shared supply, but it can also take up to 18Vdc if a player wants to run it at a higher voltage1.
Customization and price
Like all Colombo Audio Electronics pedals, the Pulse Driver is fully customizable. Based on the customization requests, the price could change significantly, so what a player pays depends on what they ask the maker to change or add1. Colombo's range includes other hand-made Italian drives such as the Colombo Utopia Overdrive, the Colombo Audio Eruption and the Southern Stalker.
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Brett Kingman
Questions
Does the Colombo Audio Pulse Driver have a real tube inside?
No. Despite being modeled on a tube circuit, the Pulse Driver is a solid-state pedal with no actual tube inside. Delicious Audio's Paolo De Gregorio describes it as recreating the 12AX7 tube design of the original without an actual tube, using solid-state stages to recreate the sound of the original circuit.
Which tubes does the Pulse Driver recreate?
The Pulse Driver uses solid-state stages that can recreate the response of three different tube types: the 12AX7, the 12AU7 and the 12AT7. Each tube type has a distinct response, so the modes give the pedal different gain and tonal characters depending on which is selected.
Can the Pulse Driver run on a battery?
No. According to Delicious Audio, there is no battery power supply. The pedal works with a standard 9Vdc center-negative power supply and can accept a voltage up to 18Vdc, which is recommended for obtaining the pedal's full character. It draws about 8mA.
Is the Colombo Pulse Driver based on the Chandler Tube Driver?
Yes. Delicious Audio describes the Pulse Driver as drawing heavily on the Chandler / B.K. Butler Tube Driver, reincarnating much of the circuitry while solving the defects of the original design. It is inspired by the sound of the 1983 B.K. Butler design.
Can the Pulse Driver be customized?
Yes. Like all Colombo Audio Electronics pedals, the Pulse Driver is fully customizable. Based on the customization requests, the price could change significantly, so the final cost depends on what a player asks the maker to build.
Sources (1)
- Colombo Audio Pulse Driver BK Butler-Style Drive, Delicious Audio, 2022-06-15
