H. J. Leak was established in 1934 and initially produced audio amplifiers under sub-contract to other companies. In 1948 they produced the product that made their name, the TL12 power amplifier.
In 1948 the problem of costly production was surmounted when we abandoned our original 4-stage circuit of 1945 for the simpler, more sensitive and completely stable 3-stage circuit of the TL12
Brunel Road, Westway Factory Estate, London, W3