Dumble Overdrive Special

The Overdrive Special is a guitar amplifier made by Dumble Amplifiers. A one-man operation in Santa Cruz, California, Howard Alexander Dumble first began producing what would become his flagship amp model in 1972,^[1] building them by hand in small numbers and incorporating bespoke changes intended to tailor the amplifier to its buyer's preferred tone and playing style.^[2] Dumble was first inspired to design the Overdrive Special after hearing Robben Ford perform with a Fender Bassman head, and as a result the amps have been described as having a "highly evolved 'Fendery'" type of tone,^[1] with a thick overdrive, long sustain, and highly sensitive dynamics.^[1] Besides Ford, players like Carlos Santana, Larry Carlton, Kenny Wayne Shepherd, and John Mayer have all owned copies. Dumble's reputation and the scarcity of his amps have made the Overdrive Special among the most renowned, sought after, and expensive models on the secondhand market,^[3] with used copies of the Overdrive Special typically selling for tens of thousands of dollars,^[2] and sometimes over $100,000.^[4]

A Dumble Overdrive Special

History

An Overdrive Special in Robben Ford's rig.

Dumble created the prototype Overdrive Special in 1972 after attending a show of Robben Ford's in which Ford played a Fender Bassman into a 2x12 speaker cabinet. At the time, Dumble was staying in Los Angeles with Jackson Browne, and Browne's band was soon playing Dumble's Ford-inspired amps. Dumble expanded his amp designs as his reputation grew, with Browne's Overdrive Specials being used by many local session musicians on hit records of the time.^[5] Ford would ultimately purchase multiple amplifiers from Dumble and become the guitarist most associated with the brand's amps.^[6] As Dumble's reputation as an amp builder grew, he also gained a reputation as an eccentric. To acquire an Overdrive Special, or any Dumble amp, one had to receive a recommendation from someone within Dumble's inner circle, followed by an in-person "audition", in which Dumble would listen to the player and determine how best to design their specific amp, assuming Dumble liked the player. Given his "off-the-grid" lifestyle, Dumble also often preferred alternative payment methods: for example, when Christopher Cross bought an Overdrive Special and two other amps, Dumble's price was a Sears washer and dryer.^[6]

Dumble spent over three decades producing the Overdrive Special, but during that time the basic circuit of the amp evolved. Copies made in the 1970s tended to be more raw-sounding, while those produced in the 1980s and 1990s took on a more refined character. Much of this was due to tone circuit changes, with Dumble removing components or adding new ones, like his "Skyliner" tone stack or "HRM" (Hot Rubber Monkey) tone stage.^[2]

As his reputation grew, Dumble's Overdrive Specials inevitably began appearing on the secondhand market, which Dumble disapproved of, since any secondhand buyer was receiving an amplifier that had been specifically voiced for someone else.^[7] Prices are typically in the tens of thousands of dollars, with some prices exceeding $100,000.^[4]

Design

While a Dumble amplifier's clean tones are highly prized by guitarists, the Overdrive Special's selling point is its overdriven tones. Unlike conventional channel-switching amplifiers, however, the Overdrive Special does not have a proper lead channel, but rather an Overdrive mode with an extra preamp tube and two additional triodes of gain following the amp's standard preamp circuit, effectively creating a cascading-gain preamp with four gain stages.^[2] Guitar Player described the amp's overdrive as a "thick, creamy, rich, yet clear and articulate lead tone that is also extremely dynamic and tactile."^[2] In its own piece, Guitar World noted the Overdrive Special is famous for its "unforgiving character", as the amp's transparentness and extreme touch sensitivity will "lay bare" any deficiencies in a player's technique.^[8] The piece further noted that the "overdrive of an Overdrive Special is powerful, and when you really get to crank it in a locked soundproof booth, it can be quite overwhelming."^[8] Producer Bob Rock stated the Overdrive Special was best-suited to virtuosos like Michael Landau, citing the amp's articulation in the hands of a gifted player.^[7]

Controls

A typical front panel feature set for an Overdrive Special includes two inputs, NOR (normal) and FET, which adds a transistor preamp stage before the preamp tubes for a brighter tone and more gain when the boost or overdrive modes are on. The clean channel's volume control follows (and stays on when the overdrive is activated), with a three-band EQ.^[9] The Overdrive Special's preamp has three mini toggle switches: Bright to add a brightness boost, Deep to change the tone section voicing from a midrange-scoop with extended bass to a mid-push and bass cut, and Rock/Jazz, with Rock having a brighter character and increased picking dynamics and Jazz being mellower with less gain. Level and Ratio knobs control the overdrive mode's output and how much overdrive is fed back into the circuit, respectively. Lastly, the Overdrive Special has Master Volume and Presence controls.^[9]

Notable players

• Joe Bonamassa^[10]
• Jackson Browne^[11]
• Larry Carlton^[12]
• Ry Cooder
• Christopher Cross^[13]
• Robben Ford^[14]
• Ben Harper^[15]
• Jason Isbell^[16]
• Eric Johnson^[17]
• Henry Kaiser^[18]
• Steve Kimock
• Sonny Landreth^[19]
• David Lindley^[20]
• John Mayer^[21]
• Carlos Santana^[22]
• Kenny Wayne Shepherd^[23]
• Mark Tremonti
• Keith Urban^[24]

See also

• Hermida Audio Zendrive, an overdrive pedal designed to replicate the sound of a Dumble Overdrive Special