The MkII, famously used by Jimmy Page during his Yardbirds and early Zep years, became so popular that Sola Sound agreed to build it under other monikers for such companies as Marshall, Vox, and Rotosound.
Photo courtesy of Stuart Castledine

The Tone Bender MkII
Only a few months after the MkI.5 arrived on the fuzz scene, the MkII was born. Arguably the most famous Tone Bender, the MkII reverted back to its original 3-transistor spec to yield a complex, harmonically rich tone with plenty of saturated, soaring gain. Like its forebears, the MkII features the dual level-and-attack control setup, and uses germanium transistors for its distinctive tone—usually OC75 transistors, though a few extant examples feature OC81Ds.

As the MkII increased in popularity, Sola Sound manufactured it in various guises for companies such as Marshall, Rotosound, and Vox—although the latter eventually took over production of their own version, which was built at JEN in Italy.

Perhaps the most well known MkII user is Jimmy Page, who used one during his tenure on guitar with the Yardbirds and in the early Led Zeppelin years. The first Zeppelin album is particularly laden with examples of thunderous MkII tone. Paired with a Telecaster and Supro amp, the Tone Bender’s classic, throaty midrange response can be heard on tracks such as “Dazed and Confused,” “You Shook Me,” and “How Many More Times.”

In addition, Donovan’s psychedelic ode, “Hurdy Gurdy Man,” features a fine example of white-hot MkII tone. Guitarist Alan Parker—not Jimmy Page, as widely thought—played the slippery solo with a Gibson SG and a MKII routed through a Fender Deluxe Reverb.

Although early Marshall Supa Fuzzes were identical to Sola Sound MkIIs, when Marshall later assumed manufacturing responsibility for the pedal, it was slightly modded for more low end. It also ended up with an inexplicable “filter” label for its attack control. Photo courtesy of Noise Floor

The Marshall Supa Fuzz
Initially made for Marshall by Sola Sound, the Marshall Supa Fuzz was essentially a Tone Bender MkII, as it had identical specs to the Sola Sound version. The longest-running production version of the MkII circuit, the Supa Fuzz was made from 1966 to the early ’70s. However, Marshall eventually took over manufacture of the pedal and modified the circuit for a touch more bass response. Confusingly, the Supa Fuzz’s attack control was mislabeled “filter” due to the fact that a different circuit design—a MkI variation in which the filter knob was a basic tone control—was initially intended to be used. Favored by Justin Hayward of the Moody Blues for its full, singing sustain, the Supa Fuzz also appeared at the feet of Pete Townshend in live shows between 1967 and ’68.

MkIII (including this Rotosound-branded specimen from 1969) and MkIV Tone Benders were overhauled to include a new treble control that yielded tones similar to the Burns Buzzaround. Photo courtesy of Chris Nelson

The Tone Bender MkIII & MkIV
In 1968, the Tone Bender went through another sonic makeover. However, rather than just losing or adding a transistor, this time the circuit was totally revamped—including with a new “treble” control. The result was a more mid-focused tone and a wider range of fuzz ferocity. The MkIII sound is so different, in fact, that it’s actually more similar in tonal characteristics to the Burns Buzzaround—a lesser-known fuzz produced in small numbers by the Baldwin Burns company in England. (At the time, the Buzzaround was King Crimson guitarist Robert Fripp’s fuzz of choice.)

The sonic similarities are not surprising as, under the hood, the MkIII circuit bears more than a passing resemblance to the Buzzaround. The MkIII was sold in various forms under a number of brands, including Sola Sound, Rotosound, Vox, and Park.

Jimmy Page was spotted deploying a Rotosound MkIII at the filming of the French TV show, Tous En Scène. Further, it is thought that Page used the Rotosound MkIII for some of the songs on Zep’s BBC Sessions double album. “The Girl I Love She Got Long Black Wavy Hair” certainly has the midrange bark characteristic of a MkIII.

A later MkIV Tone Bender featured largely cosmetic changes in the form of different graphics and enclosure style. Production of that version continued until 1976.