Harold Joseph Leak founded the seminal H. J. LEAK & CO Ltd in 1934. Originally based in London, England; LEAK was a brand that specialised in designing and manufacturing high-quality audio components.
Harold Leak marketed himself as a ‘Sound Engineer – Technician’, and along with Ted Ashley, who joined the company in the late 1930s and who later became Chief Engineer for the company, LEAK became a market leader of affordable but high-performance home audio equipment… for decades upon decades!
The LEAK brand developed amplifier technology, loudspeakers, pickups and turntables, amongst many seminal products in a portfolio spanning through the golden years of British audio innovation.
Like many of the evolutionary, and revolutionary, British audio brands of the ’30s and ’40s, LEAK was displaced by war. However, inspired by the consequential research of the war times, Leak worked on developing improved audio technology for ‘purpose’. Like many of the famous British brands of this era, LEAK was therefore initially orientated towards public address systems. The subsequent expertise in efficient loudspeaker technology combined with a desire to improve audio performance meant that, through the 1940s, low-noise, high performance and unparalleled high-fidelity systems became the focus, as LEAK conquered the world.
In the late 1940s, after the original factory in Shepherds bush was destroyed by wartime bombing, the seminal LEAK factory was founded on the newly built Westway factory estate, Brunel Road, London.
An epicentre of engineering, named after the famous engineer I.K. Brunel, the art-deco design of this factory estate very likely became part of the industrial design influence that translated through the lifetime of LEAK products.
After years of contract-based amplifier production, the LEAK Type 15 amplifier came to life in 1945 as a gem from the war-time efforts. Utilising a four-stage circuit and a groundbreaking ‘negative feedback’ design with ‘push-pull’ triode connected KT66 valves, it achieved a remarkable 15 watts output! The LEAK type 15 would be known as the original ‘Point One Amplifier’, a classic series of stereo amplifiers that evolved right through the 1950s.
In 1948, the future classic, LEAK TL/12 marked the first bold step towards high-fidelity sound reproduction. Soon a tone-arm, moving coil cartridge and a higher-powered TL/25 followed.
This high-fidelity concept required a unique approach in helping reach the mass market of audiophiles and home music enthusiasts. Therefore, in 1949 H. J, Leak embarked on a nationwide ‘live vs reproduced’ tour. Akin to the marketing campaigns of the great founding fathers of audio, Leak presented a direct comparison of ‘recorded vs live’ music with high-fidelity, LEAK powered audio systems.
Such was the response to these presentations, at short notice, H.J. Leak was invited to the Audio Engineering Society exhibition, in New York. After which, The TL/12 became a transatlantic success, with global success following very shortly afterwards!
By the end of 1949 – H.J. LEAK & CO Ltd employed 20 staff to support the innovation and production requirements of the fledging, global brand.
The TL/12 became a BBC standard in 1951, with many units being sold into the legendary BBC facilities. Specifically for BBC requirements, the TL/12 was evolved to incorporate input attenuation and a new balancing transformer.
Throughout the 1950s, new pick-ups and tone-arms reached the market too. An FM tuner arrived in 1955, in the form of the Troughline FM Tuner, and there are records and tales of innovative loudspeakers which matched 15” drivers with electrostatic HF units. Although these potentially wondrous concepts never made mass production, they formed the basis for later innovations.
In 1956, 8 years into global success with the TL/12, LEAK unveiled the TL/12 Plus, TL/25 Plus and new TL/50 plus mono amps.
Building on this further success, 1958 saw the introduction of the Stereo 20 and Stereo 50 amplifiers. Both featured all-new stereo pre-amps, embracing the mainstream adoption of high fidelity stereo home audio equipment. Not to mention a second version of the Troughline FM Tuner.
The Point One amplifier came to market at the end of the 1950s – Point One Stereo, Point One Plus (mono only) and Varisoloe Stereo models all came to market from the late 1950s through to the early 1960s. Notably, the Varislope Stereo and later introduced Varislope Mono offered the Silver and Black livery that is instantly recognized as ‘LEAK’, even to this day.
Although offering loudspeakers from way earlier in the 1950s, it was in 1959 that H.J. Leak introduced Dr Don A. Barlow to the loudspeaker development projects of LEAK. Plans for a ‘piston action’ loudspeaker. Through a process of continuous innovation, the incredibly successful and internationally revered LEAK SANDWICH was introduced, in 1961.
The Leak Sandwich was a revolutionary loudspeaker. Aptly named ‘Sandwich’ due to its diaphragm being manufactured from a section of expanded polystyrene ‘sandwiched’ between two outer layers of aluminium. As a result, this method enabled a reduction of vibrations and resonance to obtain a better, and more dynamic, reproduction of the audio signal.
The LEAK Stereo 30 was introduced in 1963. This transistor amplifier featured quasi-complementary germanium transistor output stage. Embracing a succession path from the illustrious valve amplification series, the STEREO 30 maintained the high-fidelity stereo performance synonymous with LEAK. With transistors being significantly cheaper to manufacture than vacuum tubes, the price-points of LEAK became more appealing to the masses and matched the demands of the burgeoning home hi-fi market
H.J LEAK & Co continued valve amplifier production well into the mid-’60s, and higher power models such as the TL/50Plus were still available in the late 1960s.
These changes in product portfolio and incredible demand for the LEAK SANDWICH speaker came hand in hand with the establishment of a Downham Market factory, taking LEAK from London to Norwich.
The Stereo 70 transistor amplifier came in 1968. This model utilised the classic 2N3055 transistors for the output stage, also in a quasi-complementary configuration with the result offering satisfaction to the demand for higher powered transistor- based solutions.
In 1969 H.J. Leak & Co. sold the LEAK brand to the Rank Organization, and H.J. Leak retired with the brand at its pinnacle.
Sadly, with the globalisation of an audio market and cheaper off-shore manufacturing, LEAK succumbed to the pressures of international competition, with lower costs and mass-consumer products in the seemingly ever-expanding home audio market.
After 20 years of retirement and a lifetime of audio innovation and performance defining products, Harold Joseph Leak sadly passed away in August 1989.
In 1996, the LEAK Downham Market manufacturing plant was sadly demolished, paving way for local development.
Pushed into obscurity and becoming a ‘cherished’ brand of yester-year, LEAK became another example of a strong British audio brand that would be fondly remembered but no longer an option on the home audio market.
After many years in a state of dormancy, LEAK was rescued by the IAG Group – one of the world premiere manufacturers of audio products and the owners of a plethora of classic British brands.
In 2020, the year that would mark Harold Joseph Leak’s 113th birthday and the 84th anniversary of the H.J. Leak & Co’s founding, IAG Group proudly announced the return of LEAK.
Maintaining the art-deco inspired, classic-styled high-quality home audio format for the modern-day hi-fi enthusiast, LEAK is reborn.
With close attention to detail in styling, performance and value, LEAK finally returns for the masses with the LEAK STEREO 130 and the first-ever digital CD playback device for the LEAK brand – the LEAK CDT. Offering diverse media compatibility, for the modern-day audio enthusiast, without compromising on the style and values of audio performance, the return of LEAK is the return of a legend….