Dumble Amplifiers

thumb|A Dumble Overdrive Special

Dumble Amplifiers was a guitar amplifier manufacturer founded in Santa Cruz, California in the late 1960s. In a one-man operation, Howard "Alexander" Dumble (June 1, 1944 – January 16, 2022) made each amp personally, often tailoring its design to suit the buyer's preferred tone and playing style. Dumble produced only a handful of amps per year—and just 300 in total—primarily for a clientele of well-known musicians, including Robben Ford, Carlos Santana, Larry Carlton, and Stevie Ray Vaughan. Dumble's amplifiers are among the rarest and most expensive boutique amplifiers on the used market, with the brand's flagship Overdrive Special fetching tens of thousands of dollars. Other models have sold for more. Joe Bonamassa put Dumble alongside Fender, Marshall, and Vox as one of the industry's "four quintessential guitar-amp tonalities". In 1969, Dumble produced his first amp model, the "Explosion", based on a modified Fender circuit and began earning a reputation for modding and repairing amplifiers. as well as modifying other brand's amps. Common mods included adding a master volume and his "Hot Rubber Monkey" circuit, which was an internally adjustable tone stack placed after the preamp's clipping section to help sculp the amp's distorted sounds.

Wider recognition

By the 1980s, Dumble had become known as a tube electronics master, and his growing list of high end clientele and his "off-the-grid" lifestyle had gained him a reputation as a reclusive amplifier builder to the stars.

Acquiring a Dumble amplifier

Because of his reclusive nature and methodical, one-man approach to building amplifiers, acquiring a Dumble amp was not easily accomplished. Dumble wished to make amps for only the world's best players and this did not always equate to fame in Dumble's eyes, with Dumble occasionally turning down well-known players.

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. Ben Harper said there was a "code of honor and ethics" when it came to purchasing a Dumble secondhand: "you had to make sure it was kosher with him". When Harper first reached out to Dumble about quickly purchasing a used amplifier, Dumble himself sought out potential sellers. Harper ultimately acquired a Super Overdrive Special originally made for the Beach Boys and Dumble fine-tuned it for Harper's needs, a service Dumble did for players who purchased their first model secondhand.

The Dumble sound

Because Dumble often tuned his amplifiers like the Overdrive Special to the needs of the intended player, there is arguably no singular "Dumble sound". Instead, the brand's amplifiers are renowned among players for their dynamic responsiveness and flexibility as well as their tonal palette. More broadly, Dumble's amps are often characterized as "different, more powerful, more durable, more efficient versions of a Fender Deluxe." Dumble had praised the small Deluxe combo for its "great harmonic structure at a small acoustic volume", but explained that he used a much different circuit in his amps to achieve a similarly "comfortable and very musical" tone while delivering more power. Robben Ford describes the tone of the ODS as having "a perfect sonic curve, the lows are deep and rich but not unclear, it doesn't mush out like some amps will. You have the frequencies there for your use. The mid range [is] punchy and clear and the high end, bright, clear but doesn't hurt your ears. It's loud but it sounds good."

In an interview with Premier Guitar, Ford claims that Dumble told him that the original inspiration for the Overdrive Special came while watching Ford play live in the 1970s at a bar in Santa Cruz. Ford was using an early-60s 6G6-A Fender Bassman, and running an Ibanez Tube Screamer in front of it to overdrive the tubes to breakup. Supposedly, Dumble liked Ford's sound, and while contemplating it had the revelations that led to the original Overdrive Special. Since buying a ODS, Ford has almost exclusively used his original Dumble or an exact clone of it in live performances.

Overdrive Reverb

An Overdrive Reverb is an Overdrive Special amplifier with an internal Reverb Circuit.

Steel String Singer

The Steel String Singer is an adjustable single channel "clean" amplifier with reverb.. Fewer than 12 of the original Steel String Singers have been accounted for.

As is typical with Dumble amplifier models, the Steel String Singer (SSS) varies from serial number to serial number. For example, The first SSS (made for Henry Kaiser) has a built-in vibrato circuit. Also, despite its reputation for a clean sound, the earlier SSS (and possibly #7) breaks up when the input gain is turned up or pushed by a strong input signal.

Manzamp

A single channel "no frills" combo amplifier, similar in appearance to the tweed Bassman. It was the most expensive amplifier on Dumble's amplifier price sheet in the 90s. Bonnie Raitt is a notable original owner of a Manzamp.

Dumbleland

One of the earliest Dumble amplifiers, it was also the model which Stevie Ray Vaughan and Double Trouble used for 80% of the guitar tracks on their debut album, Texas Flood, which was recorded at Jackson Browne's studio. Browne was a long time friend of Dumble, and owns some of his earliest amplifiers (including the first Overdrive Specials). Jackson Browne's collection of amplifiers introduced Vaughan to Dumble's amps, and Browne introduced Vaughan to Dumble so that he could buy his first Steel String Singer.

Winterland

The Winterland was a 300-watt bass amplifier Dumble made in the 1970s.

Tonestacks

Despite the variability among Dumble tonestack voicing and operation, most Dumble amplifiers have certain controls in common:

Bass, Middle, and High frequency potentiometers
Two voicings to choose from: Jazz, and Rock
Boosts for each frequency–deep, and bright (some have mid boosts)
An EQ bypass that bypasses the tonestack entirely (some models have an actual boost rather than a bypass)
Overall power amp Presence control, or a Contour tone cut (most have one or the other, but some have neither)

Dumbleator

left|250px|thumb|Dumbleator

left|250px|thumb|Dumbleator II

Dumble also made a tube-buffered external effects loop called a Dumbleator. A few Dumble amps have a Dumbleator circuit built in, but most have "un-buffered" input jacks that tap directly out of the pre-amp and into the power amp. Dumble likely created this external loop because of the difficulty of fitting effects loop buffering into the amplifier chassis (and the limited use of effects loops for most players). The Dumbleator has separate Send and Receive controls for the effects, and a Bright switch on at least the return. Later models also have a Bright switch on the send control. Dumble also made stereo versions. This effects loop buffering is essentially a cathode follower for the send, into a gain stage for return.

Notable players

Eric Clapton (has used various Dumble amps and Dumble modified/refurbished Fenders over the years)
Sonny Landreth (Overdrive Special)
Stephen Bruton (had a low-watt Dumble with 4x10" speakers)
Larry Carlton Overdrive Special
Robben Ford (bought an Overdrive Special in 1983 and had a model custom-built in 1993/4)
David Lindley (original owner of Overdrive Special #2, and Steel String Singer #3, and used them in stereo live)
John Mayer (Steel String Singer–also has a large collection of used Dumble amplifiers)
Lowell George had an early custom Dumble head he used for most of his career.
Carlos Santana (has at least one Overdrive Reverb and a Steel-String Singer purchased in the early 2000s, and uses Bludotone clones of his Dumbles live besides his Mesa Boogies)
Stevie Ray Vaughan (Steel String Singers–original owner of both #7 and #8, and had an association with #9)
Henry Kaiser (1978 Dumble Overdrive Special, original and current owner of Steel String Singer #1, original owner of SSS #4, and other ODS's as well)
Joe Bonamassa (owns multiple Overdrive Specials, including one formerly owned by Lowell George)
Keith Urban (Overdrive Special)
Steve Kimock – 50-watt and 100-watt Dumble Overdrive Specials
Ben Harper – 3 × Overdrive Specials (50w head + 2×12" Cabinet, 100/50w 1×12" Combo, and a 100/40w Head + matching 1×12" Cabinet); in March 2016, Harper explained that Dumble had him plug his guitar directly into the oscilloscope so he could note the frequency patterns of Harper's instruments and voice Harper's Overdrive Special accordingly
Kirk Hammett (Steel String Singer)
Jason Isbell (Dumble modified Fender Pro and Dumble Overdrive Special)
Kenny Wayne Shepherd (Dumble modified Tweed Deluxe, nicknamed "Tweedle-Dee.")
Jackson Browne (Original owner of Overdrive Special #1, Dumbleland, and Steel String Singer #2)
Ry Cooder was an original owner of the Dumble Borderline Special (a 50 watts Overdrive Special with added tremolo effect). According to some sources he got so fed up of waiting for repairs or customizing, that he put the amp head in Dumble’s driveway and drove over it with his car, destroying the amp.
Christopher Cross recently said in an interview with Rick Beato that he recorded a lot of hits such as “Ride like the Wind” and many others using various Dumble Overdrive Specials.
Mark Tremonti in a 2024 AMS interview on You Tube said that he owns 4 Dumbles