H.J. Leak & Co., London: High Fidelity since 1934
In 1934 Harold Joseph Leak founded H.J. Leak & Co in London, UK – and promotes the company with his own name, adversting himself as “Sound Engineer – Technician”. In 1936 Leak & Co. release a P.A. Amplifier, with exhibits at Olympia Exhibition. 13 Watts output using push-pull PX25 power triodes. 40Hz to 12kHz +/- 1dB.
H.J. Leak does not appear in listings of exhibitors for Olympia, so the company may have used another company’s stand for the exhibit). This amplifier was supposedly advertised in Wireless World around 1938, although a search has failed to locate the advertisement. About 1949/1950 the Leak “550” two-way moving coil loudspeaker was released. This loudspeaker was used in the many live-versus reproduced sound demonstrations Harold Leak conducted. Harold Leak died on August 27, 1989.
Source: www.44bx.com/leak
H.J. Leak & Co.: the short history
The original page covers Leak's early public-address work and stops around 1950. The part it skips is the one that made the company famous. In September 1945 Leak released the Type 15, the first "Point One" amplifier: 15 watts at 0.1% total harmonic distortion, with KT66 valves connected as triodes and 26 dB of feedback over four stages. The name came straight from that distortion figure, at a time when around 2% was considered acceptable.
In 1948 the three-stage TL/12 matched that performance at lower cost, and later models such as the TL/10, TL/25-Plus and Stereo 60 kept its layout with ultra-linear output stages. The Rank Organisation bought the company in January 1969, and production under the Leak name ended in the late 1970s. Wikipedia's account of the 1930s also mentions Osram DA30 triodes and a 45-watt design, alongside the PX25 amplifier the original page describes.
| Founded | 1934, London |
|---|---|
| Founder | Harold Joseph Leak |
| Point One Type 15 | September 1945: 15 W at 0.1% THD, KT66 triode-connected |
| TL/12 | 1948, three-stage |
| Sold to | Rank Organisation, January 1969 |
| Harold Leak died | 27 August 1989 (original page) |
Questions collectors ask
What does Point One mean on a Leak amplifier?
It refers to the 0.1% total harmonic distortion of Leak's 1945 Type 15 amplifier, a very low figure for the time.
When was H.J. Leak & Co. founded?
In 1934, in London, by Harold Joseph Leak.
Who owned Leak after 1969?
The Rank Organisation, which bought the business in January 1969.
Sources: Wikipedia: LEAK.
