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Photo from jacksonampworks

Dumble Steel String Singer history

It is worth noting that there is no single, definitive source of information on Dumble amplifiers. In gathering our data, we relied primarily on The Amp Garage forum, which we consider to be the most reliable source. We also analyzed available photographs and schematics, using them to draw conclusions that we have compiled into a cohesive whole.

The genesis of the Steel String Singer amplifier is a process of evolution from a powerful bass amplifier to the most exclusive guitar amplifier in history. It can be summarized in three key steps:

1. Roots in the '60s 

Few know that in his youth, Alexander “Howard” Dumble played the bass. Although he became world-famous as an amplifier builder for electric guitarists, he spent a significant amount of time on stage with a bass guitar in hand. And if he hadn't played the bass, the famous Dumble amplifiers probably wouldn't even exist! As a teenager in the 1960s, he learned to play the traditional electric guitar and worked as a session musician in Hollywood. The most important moment in his music career came in 1968, when he was hired as a touring bassist for the well-known folk-rock singer and activist Buffy Sainte-Marie. He went on a very large and lucrative tour with her. It was the money earned during this tour that allowed him to move from his backyard into a professional building in Santa Cruz. There, in 1968, he opened his first official workshop under the Dumble Amplifiers banner.

The Soul Folk - first from the right: young A.H. Dumble - photo from bakersfield.com

Since Alexander „Howard” Dumble played the bass extensively in the late 1960s, he perfectly understood the needs of rhythm section musicians. He noticed that the bass amplifiers of that era easily distorted the low end and lacked dynamic response. This personal experience pushed him to design the powerful, clean-sounding Dumbleland model in 1966 - an amplifier originally intended for bass players. The design relied on a massive power section, top-tier transformers, and four 6550 power tubes. This allowed it to generate 150W RMS and achieve an unprecedented amount of clean headroom without any audio distortion.

Dumble Dumbleland 150W - photo from reverb.com

The success of this design, combined with Dumble's touring experience in the late 1960s and early 1970s, resulted in another, even more powerful project. Inspired by the demand for extreme bass amplification on grand stages (such as the famous Winterland Ballroom in San Francisco), Dumble created the Winterland Bass Amplifier - an uncompromising monster driving up to 200W RMS. Over time, during the 1970s, this line of powerful amplifiers underwent an evolution; based on the Dumbleland platform, the Dumbleland Special was born, dedicated strictly to the electric guitar. Sources state that he built 10 units of this model.

Dumble Winterland 200W stack - photo from reverb.com

Dumble Dumbleland Special #009 - photo from amparchives.com (this source page loads very slowly)

In the early 1970s, Alexander “Howard” Dumble relocated to Los Angeles. By then, Jackson Browne was already a rising star in the folk-rock scene and possessed excellent connections within the local music community. The two men hit it off instantly. Browne was fascinated by Dumble's technical genius, while Dumble needed a stable place to live and grow his business. Jackson Browne allowed Dumble to move onto his private property. Furthermore, he provided him with a dedicated space where the builder could construct and test his creations without any interruptions. It was during this period that Browne became one of Dumble's most crucial patrons. He bought nearly every new prototype and experimental model that left the workshop. As a result, Browne was among the first musicians in the world to own models like the Overdrive Special or the customized Dumbleland Special DS-150 #005.

Jackson Brownie and his Dumble Overdrive Special - photo from youtube.com

Since Alexander “Howard” Dumble lived right next door, Browne's amplifiers served as the perfect testbeds for his innovations. Dumble regularly brought the Dumbleland Special #005 back to his workshop to solder in new ideas, swap capacitors, and modify the frequency response. It was precisely because of this that the Dumbleland acquired a unique, modified midrange, which later paired so incredibly well with Stevie Ray Vaughan's guitar! Consequently, the amplifier found its way into Browne's studio (Downtown Studios) in the most natural way possible - as the fruit of a close friendship and the immense support the musician provided to the young builder at the very start of his legendary career.

Dumble Dumbleland Special DS-150 #005 - photo from IG johnmayergear

In 1982, Stevie Ray Vaughan and Double Trouble walked into Jackson Browne's studio in Los Angeles. The band had no money, so Browne let them use the studio for free for a single weekend. SRV plugged his guitar into the Dumbleland Special #005 sitting right there in the room. They tracked the material live, with the entire band playing together in the same room. The guitar tone was so massive, deep, and crystal clean that upon the release of the Texas Flood album in 1983, the entire guitar community was left in shock. Everyone wanted to know what that kid from Texas was playing through. Dumble's reputation exploded overnight!

Jackson Browne: "When Steve came to L.A., he started playing this Dumble amp that we had laying around, that we called the "Mother Dumble" because it was kind of like the first one Howard Dumble built."

2. The Breakthrough and the Birth of the Steel String Singer

Around 1980, avant-garde guitarist Henry Kaiser asked Dumble to build an amplifier that would retain the power and purity of the Dumbleland Special, but offer far greater capabilities for shaping guitar tone. A.H. Dumble modified the Dumbleland Special design and added both reverb and tremolo. This was a powerful element of its magic and another huge difference compared to the raw Dumbleland Special, which had neither reverb nor tremolo at all. Interestingly, this first unit was built as a 100W combo amplifier, and the tremolo circuit as well as this cabinet format were unique to this specific #001 model; neither feature appeared in any subsequent SSS models, as all following units were built strictly as amplifier heads. Henry Kaiser went on to order another Steel String Singer unit - this time built as an amplifier head, bearing serial number #004.

Dumble Steel String Singer #001 combo version - photo from ampgarage.com

Dumble Steel String Singer #004 (owned by John Mayer, originally commissioned by Henry Kaiser)
Photo from IG amparhives.com (this source page loads very slowly)

3. Explosion of Popularity

Before diving into the chronology of the Steel String Singer's creation, we must address the controversial topic regarding the serial numbers of individual units. Numbers #001, #002, #003, #004, #005, and #010 are 100% confirmed. The proof lies in photographs where the amplifier's number is clearly visible, or we know from other reliable sources who their first owner was. From available photos of Stevie Ray Vaughan's gear, we know he owned three SSS units (one "Silverface" and two "Blackfaces"), yet in one interview, Vaughan explicitly states he had four units. In that case, what about the fourth SSS? In 2025, at The NAMM Show, this mystery was solved. At the booth of the "reactivated" Dumble company, a mysterious amplifier was displayed with the description "Steel String Singer #008". In reality, it was a Dumble Special converted into a Steel String Singer! Therefore, it should be assumed that the "Silverface" named "King Tone Consoul" is number #006, and the other two "Blackfaces" are numbers #007 and #009. The numbering is completed by number #008, which was mistakenly assumed to be one of the "Blackfaces". So, where is the point of contention? On The Amp Garage forum, it was assumed that SRV owned units #007, #008, and #009, and that Dumble allegedly did not finish #011 before Vaughan's death... What about number #006? It was assumed that its whereabouts are unknown, or that it was never built at all... Today we know that #008 is an SSS in a Dumble Special chassis/headshell, so #008 cannot be a "Blackface". From a logical standpoint, serial numbers #006, #007, #008, and #009 seem highly likely to be SRV's amplifiers. Our thesis is supported by a description of unit #005 posted by blackmagicguitar on Instagram, which notes that "Dumble SSS #005 was built for Eric Johnson, while units 6/7/8 went to SRV". We want to emphasize once again that the cited numbering of Vaughan's individual SSS units is our conjecture, as there is no single reliable source (other than number #008) to confirm it. There is also no other photographic documentation proving that there were more than 10 SSS units in total. Looking objectively at all this confusion, one must realize that practically everything surrounding A.H. Dumble and his amplifiers is shrouded in a touch of mystery, and the numbering serves only as a reference point for the chronology of their creation.

Steel String Singer #006 "Silverface" - photo from FB Stevie Ray Vaughan

Dumble Steel String Singer #007 "Blackface" - photo from thesubjectmatter.com

Dumble Steel String Singer #008 - photo from ampgarage.com

Dumble Steel String Singer #009 - photo from ampgarage.com

As we wrote earlier, in 1982 Stevie Ray Vaughan recorded his debut album Texas Flood at Jackson Browne's studio. He used the aforementioned Dumbleland Special #005 there. Enchanted by the dynamics and sheer power of that sound, he met with "Howard" Dumble and ordered two 150W Steel String Singers with the characteristic chicken head knobs. Shortly after, Vaughan became a top-tier star of the blues scene, and along with his popularity, Dumble amplifiers gained massive renown in the guitar world!

It is worth mentioning that before building the SSS for SRV, A.H. Dumble had already built several units for other musicians:

Dumble Steel String Singer #002 "Silverface" 100W version. 
(owned by John Mayer, previously located in Japan with its second owner, and originally commissioned by Jackson Browne)
Photo from jacksonampworks

Dumble Steel String Singer #003 "Silverface" / Snake Skin tolex, 100W version. 
(owned and commissioned by David Lindley)
Photo from ampgarage.com

Dumble Steel String Singer #005 "Silverface" 150W version. 
(owned by Santana, with two previous owners, and originally commissioned and owned by Stephen Bruton and Eric Johnson)
Photo from IG blackmagicguitars

Dumble Steel String Singer #010 "Blackface" 150W version. 
(originally commissioned by Stevie Ray Vaughan for his pal Jeff Healy. It passed to Colin James, then Kirk Hammett and ultimately Carlos Santana)
Photo from IG blackmagicguitars

What is the Steel String Singer phenomenon?

In short, the SSS was based on a revolutionary idea: combining high power with a crystal-clear preamp. As a result, an amplifier with a gigantic, previously unseen headroom was created. Alexander Howard Dumble, like few others in those days, had huge experience in building high-power tube amplifiers (Dumbleland, Winterland, and Special 16). Utilizing this knowledge in an absolutely brilliant way, on the basis of the Dumbleland Special, he built - in our opinion - the best-sounding amplifier in the world. Interestingly, no company producing tube amplifiers has managed to repeat such a powerful and clean brzmienie to this day. It is true that Fender in the years 1976–1980 released the Super Twin model with a capacity of up to 180W RMS, however, it did not even come close to the hi-fi sterility of the Steel String Singer. It should also be emphasized that the SSS works wonderfully with TS-9 type effects, which was often a pain point of Fender constructions. If we add a "killer" sounding spring reverb to this, we can tempt ourselves to say that it is an ideal tube amp! On top of that, due to its extremely limited production run, it has become the ultimate Holy Grail today. So that it is not so colorful, there is a fly in the ointment- it is its dimensions, weight, and quickly wearing out tubes.

Dumble Steel String Singer #001 front chassis - photo from IG gabe_bergman

The History of the Japanese Hand-Drawn Schematic

To realize how deeply shrouded in mystery the Steel String Singer was and how difficult it was to replicate, we must recall a certain event that changed everything. Alexander Dumble built the amplifier with serial number #002 in 1981 for his friend, Jackson Browne. Shortly after, Browne sold part of his collection, and the amplifier was purchased by a wealthy collector from Japan named Takahiro. In December 2007, the owner brought the amplifier to a repair shop called tbaudio (T.B. Audio) for servicing. At that time, Dumble was not yet gooping the circuit boards - where he soldered the capacitors and resistors - so the components and their connections were completely visible. An engineer at the shop took photos of the interior (so-called "gut shots"), while his colleague Masahiro simultaneously sat by the "open" chassis and reverse-engineered it. Based on the physical layout of the components and with his colleague's assistance, Masahiro drew that legendary schematic in pencil on paper ("the hand-drawn schematic"). Both the photos and the handwritten schematic were subsequently posted on tbaudio's private blog.

The hand-drawn schematic featured a preamp

The hand-drawn schematic featured power amp and power supply

These materials first leaked into the Asian web, causing a massive stir among guitar geeks. The Amp Garage community quickly caught on, and the famous gut shots alongside the hand-drawn schematic files promptly surfaced on the forum. This triggered an absolute earthquake. For the first time, users saw the official SSS architecture. Over time, it turned out that the Dumble Steel String Singer #002 schematic contained minor errors. Forum builders spent hundreds of hours analyzing the Japanese gut shots to correct and verify every single resistor and capacitor value. While the world was copying the Japanese hand-drawn schematic, the amplifier was put up for sale in Japan. John Mayer caught wind of this. He bought it back for a staggering amount and brought it back to the USA. To this day, Mayer uses this exact "Japanese" unit as the foundation of his tone on major concert tours.

The Japanese "gut shots" of the Dumble Steel String Singer #002 chassis interior (original version)

Dumble Steel String Singer #002 chassis interior (AI-enhanced image)

D-Tone Steel String Super chassis interior

The build differences between specific units

As with all Dumble amplifiers, individual units varied from one another, and the SSS was no exception. The available schematics for units #001, #002, #004, and #005 show that each featured unique tonal solutions, although the overall amplifier architecture remained very similar across all these pieces. We do not know the exact details regarding units #003 and #010, nor those used by SRV (#006–#009). No gut shots (internal photos) of these units are available, and consequently, no schematics exist. While alleged specifications for these units are cited on The Amp Garage forum, in our opinion, these are likely just conjectures extrapolated from Dumbleland schematic analyses.
What we know for sure (except for #008):
1. #001–#005 were 100W amps (4x6L6) featuring Fender-by-Schumacher transformers and a 7-step filter positions on a HIGH and LOW filter.
2. #006–#010 were 150W (4x6550) featuring transformers salvaged from Peavey amplifiers and an 11-step filter positions on a HIGH and LOW filter.
3. All units except for #004 featured a Cathode Follower Driver tube after the phase inverter tube. 
4. Serial number #001 featured a single-tube 12AX7 Opto Roach-style tremolo, which never appeared in any other SSS. It also lacked the DEEP switch and FET channel.
5. From unit #003 onward, all featured a PAB (Preamp Boost) hidden within a 3-way JAZZ/PAB/ROCK switch, and the ACCENT switch was replaced by a PRESENCE control. 
6. From unit #004 onward, a FET GAIN control was introduced, which was moved from the internal FET PCB to the amplifier's front panel.