The odd model designation for the ‘MK1.5’ refers to the way that this model sits, chronologically, in between the first version of the Tone Bender, known informally as the ‘MKI’, and the version that Sola Sound began to offer in late 1966, which was officially designated the Professional MKII.

A useful way of looking at this model is by considering it to be a transitional Tone Bender, built between the famous three-transistor ‘MKI’ and Professional MKII models.

As with the ‘MKI’, the ‘MK1.5’ moniker is one that was only applied to the two-transistor Tone Bender by collectors in modern times. Until Sola Sound released the Tone Bender Professional MKII, their pedals were all known simply as ‘Tone Benders’ (unless branded otherwise).

According to witness accounts, the ‘MK1.5’ was being sold at a variety of different shops across the UK, including by Jennings in Dartford. These pedals were likely sold at Macari’s own chain of Musical Exchange shops in London, although there is no first-hand evidence to corroborate this yet.

1966 Tone Bender MK1.5
1966 Tone Bender ‘MK1.5’

The origins of the ‘MK1.5’ are still in dispute, and there is no consensus as to whether the model was conceived by Gary Hurst, by Dick Denney, or perhaps by somebody else altogether.

Early ‘MK1.5’ Tone Benders date to 1965, which means that there is a possibility that it was being produced alongside Gary Hurst’s ‘MKI’ Tone Bender for a while. Date codes on the potentiometers of surviving pedals also prove that the ‘MK1.5’ was still in production by May of 1966.

In 1966, Sola Sound also started acting as an OEM. This meant that, alongside the official ‘Tone Bender’ fuzz boxes, the company was also supplying the same product on behalf of a number of other brands.

The same electronics that were built into the grey (and sometimes gold) Tone Benders, found their way into similar cast aluminium housings, but branded instead for companies such as Dallas [Rangemaster Fuzzbug] & Rotosound [Fuzz Box].

A generic, unbranded ‘Fuzz Box’ featuring a ‘MK1.5’ circuit was also briefly offered in 1966, and the anecdotal evidence surrounding one particular surviving example reveals it to have been originally sold by a music shop in Ireland.

Later in that year, Sola Sound would discontinue the ‘MK1.5’ Tone Bender, and offer a modified version of the same circuit under its own, as well as under other company’s brands, as the now-famous Tone Bender Professional MKII.

Tech specs

Compared with the earlier ‘MKI’ Tone Bender, there isn’t much to see inside an original example of a ‘MK1.5’. The small square of stripboard is populated with a ‘textbook’ negative-feedback amplifier circuit, typically with two Mullard OC75 germanium transistors (although some early ‘MK1.5’s’ were fitted with Impex S3-1T transistors instead).

During the early stages of the ‘MK1.5’s’ production, the pedals were fitted with a 500kΩ level potentiometer, as opposed to the typical 100kΩ pot that most schematics describe. The larger value level pot extends the lower frequency cut-off, and allows for a bassier fuzz sound. Because Arbiter’s Fuzz Face (released in late 1966) features almost identical parts values, including a 500kΩ level pot, it is very likely that Arbiter used an early ‘MK1.5’ for reference whilst designing their own fuzz box.

Circuit board inside a 1966 Tone Bender MK1.5
Two original MK1.5 Tone Benders
Two original ‘MK1.5’ Tone Benders (Photo credit: C. Nelson)

Notable users

Contrary to popular belief, the Tone Bender ‘MK1.5’s were actually manufactured in fairly large quantities, considering the relatively short period of time that the model was around for. Exact production numbers are sadly unknown, but vintage examples of the ‘MK1.5’ resurface fairly regularly, and with over 40 known surviving original pedals, they are far more abundant than many of the fuzz boxes built by Sola Sound’s competitors during 1966.

Because a portion of the stock of ‘MK1.5’ Tone Benders was modified to three-transistor Tone Bender MKII specifications, whilst retaining the same enclosure & hardware, it is almost impossible to determine from period photos which version of the Tone Bender a celebrity musician might have used. The grey Tone Benders that artists such as Jimmy Page (Yardbirds & Led Zeppelin), Syd Barrett (Pink Floyd) & Mike Ratledge (Soft Machine) were photographed using could have been built with either ‘MK1.5’ or MKII circuits.

The Beatles were photographed in the studio with a Tone Bender in April 1966.1 Based on the type of enclosure, and the timing of the photograph, in this instance, it is almost certain that the pedal in the photo is a ‘MK1.5′ Tone Bender. It’s unknown, however, whether this pedal was actually used for any of the Beatles’ recordings.

Testimonies and physical descriptions from original owners of Tone Benders reveal a number of specific songs that were recorded with the ‘MK1.5′. These include Him & The Others’ ‘I mean it‘, the Transatlantics’ ‘Don’t fight it‘, and Downliners Sect’s ‘Glendora‘.

(Thanks to T. Clemson, G. Gibbs & J. Edmonds.)

Another particularly notable user of the ‘MK1.5’ Tone Bender was Mick Ronson. Before going onto global fame in the early 1970s, alongside David Bowie, Ronson played guitar with the Mariners and with the Crestas in the Hull area. Mick briefly lived in London, during the mid 1960s, playing guitar for the Voice, but returned to Hull in 1966 to join a newly-reformed Rats.

It is not known how or from where Mick originally obtained the ‘MK1.5’, but Mick’s pedal still survives (and is pictured below). The electronics in this ‘MK1.5’ date to early 1966.

Original 1966 Tone Bender MK1.5, formerly belonging to Mick Ronson

According to a childhood friend of Mick’s (and also the current owner of his ‘MK1.5’ Tone Bender) at some point in the 1960s the Rats showed up at his address, where Mick gave him the Tone Bender, along with a ‘grey’ JMI/Vox wah-wah and a Marshall speaker cabinet. Mick allegedly did not need the pedals anymore, as he had replaced them with a different fuzz box that he preferred. This sequence of events matches up with Keith Cheesman’s own memory of Mick returning from London with the ‘MKI’ Tone Bender2 that would famously be used throughout his tenure with the Spiders from Mars.

(Many thanks to R. Wilkinson for the photo and history behind this pedal.)

Distant cousins

The famous ‘Vox Tone Bender’ (model v828), pictured below, is easily mistaken for the two-transistor ‘MK1.5’ Tone Benders, because they were built in a very similar style enclosure, and featured a very similar two-transistor fuzz circuit. Unlike the British-built Tone Bender ‘MK1.5’, however, the Vox ‘v828’ Tone Benders were manufactured in Italy until the early 1970s. They were initially made by EME (Elettronica Musicale Europea), which was the company also responsible for building organs & wah-wah pedals under the Vox brand. Production was later taken over by the newly founded company, ‘Jen’. This Italian-built Vox Tone Bender was apparently intended for the American market. The model ‘v828’ appears in Thomas Organ catalogues from the time, and surviving examples overwhelmingly also resurface in the United States.

British & Italian two-transistor Tone Benders
The British-built ‘MK1.5’ Tone Bender (left) and its distant Italian-built cousins, model ‘v828’ (middle & right).

Despite sharing the same model name & circuit topology, the Vox Tone Bender should not be attributed with the ‘MK1.5’ moniker. As to avoid confusion, a sensible way of differentiating between the two is by attributing the Italian model with its model number, as listed in period catalogues (namely ‘v828’). After all, the ‘MK1.5’ moniker refers to a very specific Sola Sound fuzz box: a de facto ‘missing link’ between the ‘MKI’ and Professional MKII.

Thanks to T. Clemson, G. Gibbs, J. Edmonds & R. Wilkinson

  1. Freeman, Robert, 26th April 1966, The Beatles Recording [https://fuzzboxes.org/beatlestonebender]
  2. Keith ‘Ched’ Cheesman, interviewed in 2007 for Whotabs [https://www.thewho.net/whotabs/gear/guitar/tonebender.html]

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