The Amazing History of Dumble Amplifiers

Few guitar amp designers have achieved the same notoriety as the musicians who made their amps famous. Sure, Leo Fender and Jim Marshall are exceptions, but then there's Alexander "Howard" Dumble.

Here, we'll learn about the man behind decades of rare handmade custom tube amps that bore his name — and routinely fetch prices of $200,000 or more — and delve into the history of his most iconic creation, the Dumble Overdrive Special.

Building a Foundation for Greatness

Alexander Dumble came from humble beginnings. A football player for Bakersfield California’s East High School, he was inspired to explore electronics after repairing his school’s PA system.

“He was a tinkerer,” explains James Santiago, Senior Product Designer at Universal Audio. "Dumble read the books and could execute.”

It didn’t take long for Dumble to make a name for himself as a savvy electronics specialist. By the age of 20 he was contracted by fellow Bakersfield native Semie Mosley to build a series of Amplifiers for influential instrumental giants The Ventures under the Mosrite brand.

"The Ventures played through them and were really interested, but it was a little too much rock for them," Dumble told Guitar Player in 1985. "They wanted me to go into business with them, but I decided against it, and went back to playing in studios and in rock bands."

Touring as a bassist with Canadian singer-songwriter Buffy Sainte-Marrie, Dumble eventually raised enough funds to open a workshop in his new environs, Santa Cruz, California on East Cliff Dr.

And in 1969, the first Dumbles were born.

Dubbed the “Explosion” amps, these models took inspiration from the PA heads and Fender amps Dumble modded and repaired over the years.

By the 1970’s, with a growing reputation for modding and repairing Fender-style amplifiers, Dumble was on the verge of exciting new opportunities. And he was on the move.

1970’s: Birth of the Overdrive Special

Throughout the early '70s, Dumble moved between Los Angeles and Santa Cruz, making connections with various pro guitarists who had emerged in California in the wake of the West Coast rock and roll and counterculture movement of the late-’60s.

“At some point, he and a friend decided to move to Santa Cruz because it was a much better scene, with more musicians than Bakersfield,” says Santiago.

One of Dumble's most famous Santa Cruz builds from this time is the Overdrive Special Reverb built for Little Feat legend Lowell George in late '75, early '76.

"It's like a Fender made right," George told Guitar Player in 1977. "It's the best amp I've ever played through."

During this time, Dumble developed a friendship with Jackson Browne, staying at his property in Los Angeles while working on the first prototypes of the Overdrive Special. Soon after, Browne and his band were rocking ODS amps.

“The Running on Empty solo was a landmark,” says Santiago of the title track from Jackson Brown's 1977 album. “That was actually a live recording, and the early Dumble ODS that David Lindley played had this classic slide tone.”

These first ODS amps featured a 6L6-driven power tube section and cascading gain stages, a feature which would become a hallmark of the Dumble sound.

“Some of the early Mesa Boogie Mark I and Mark II amps had cascading stages as well, very similar to Dumbles,” says Santiago. “But who did it first? You've got two California guys basically fighting it out for who invented it.”

While there’s still debate as to who invented this feature — whereby repeating tone stacks progressively amplify gain for added clipping and overdrive — both Dumble and Randall Smith are considered the first to employ cascading tone stacks.

As Dumble’s reputation grew throughout the 1970s, so too did his amplifier designs. In this period he built numerous custom amps for session players and prominent studios in LA, each with bespoke qualities specific to their needs.

Perhaps the most notable of these custom features was the addition of a master volume, as well as the “Hot Rubber Monkey” circuit.

This feature was essentially an internally-adjustable tone stack located after the clipping section of the preamp, which allowed the player to sculpt the distorted sound of the amp, while maintaining a master volume for both the clean and overdrive channels.

“With the HRM circuit, he disconnected the second master volume,” explains Santiago. “So he got rid of a bunch of loading by not going to that second master.”

1980’s: Widespread Recognition

By the 1980s, Dumble had cemented himself as the custom amp builder for a cadre of legendary A-List tone hounds.

And If you turned on the radio in the '80s, you definitely heard a Dumble.

Jackson Browne’s collection of Dumbles started appearing on an impressive roster of hits throughout this period.

The following year, session legend Rick Vito used Browne’s Overdrive Reverb on solos for "Tender Is the Night" and "For a Rocker" from Browne's album, Lawyers in Love.

And although it wasn't included on the record, Vito's work on the track "Somebody's Baby" highlights the ODS's cleanish grind.

Later, in 1986, Vito used the ODS on an even bigger hit, for the lyrical slide solo on Bob Seger's "Like a Rock."

Of course the guy who played on more hits than any other guitarist in the '80s, Steve Lukather, here with a wound-up ODS.

Luke praised his ODS for its clean tones too, pointing to his work on Quincy Jones' album, The Dude.

Throughout this era, Dumble created various iterations of the preamp circuit in the ODS, using different tone stacks such as Skyliner, Bluesmaster, and Ripper.

From the '80s Onward: The Tone Connoisseur's Amp

Robben Ford discovered the ODS while renting one for session work in the early-’80s. Ultimately, Ford purchased his first Overdrive Special in 1983, and had another built around ’93 or ’94.

Ford quickly bonded with the amp, not surprisingly, as allegedly Dumble was inspired to create the ODS after seeing Ford perform at a bar gig playing through a piggyback Fender Bassman on a 2x12 cab in the early '70s.

"The tone curve on my ODS is so perfect," Ford told Vintage Guitar in 2007. "The lows are low, but don’t get woofy and mushed out. The mids are punchy and very strong, and the high end is clear but not ear piercing. All the frequencies somehow are just so righteous and very even."

Another famous Dumble user, studio legend Larry Carlton, relied on his ODS for three decades. His 1987 album Last Nite, is regarded by many as the definitive example of "Dumble tone."

And even though he's mainly associated with the Dumble Steel String Singer, Eric Johnson used an ODS on this classic track, recorded at Ocean Way Studios.

The 1990s brought about a dip in the popularity of Dumble amps.

With the landscape of guitar-driven music shifting to favor higher gain tones, many mainstream guitarists opted for Marshall JCMs, Mesa-Boogie Dual Rectifiers, or external effects pedals to get more distortion from their amps.

Still, many of the session players who had grown loyal to their Dumbles held fast to the versatility and reliability of the amps. Players like Sonny Landreth and Carlos Santana continued to champion Dumble amplifiers throughout the 1990’s and 2000’s.

This was also a period of experimentation for Dumble. With many long-term clients coming to him for repairs or new amplifier orders, he was able to further refine his circuits to suit the needs of his impressive roster of pro players, including Carlos Santana.

Along with Santana, there is currently no greater exponent of Dumble tone and lore than John Mayer, who over the past two decades has been known to scoop them up every chance he gets.

These days, it’s rare for the everyday guitarist to have seen a Dumble amp in person, let alone played through one.

The exceedingly rare and coveted nature of his creations owes to Dumble’s mastery of his craft, but also a seemingly spiritual bond that he formed with each amp, as James Santiago explains.

“If you were lucky enough to own a Dumble, you didn’t own that amp. It was still Alexander’s until the end.”

With Howard Dumble’s passing in 2022, original ODS amps have never been more coveted, and his vision ultimately lives on through the classic recordings and players who continue to use his amps on stage and in the studio.

“Dumble didn't give a shit about running a company,” says James Santiago. “That guy wanted to build one amp at a time.”

“He was a singular force. And there’s something to be said for someone whose artistic vision was so high that he only wanted to work with guitarists who were doing new things. He didn’t want to make a Fender or a Marshall or a Vox — there was no going backwards.”