Burkat Shudi died in 1773, and John Broadwood took control of the company from his brother-in-law in 1783.
Broadwood and his acquaintances William Stodart and Americus Backers are credited with devising the English Grand Action, an early piano action, and of taking piano design from the box piano to a prototype grand piano. In time his sales of pianos exceeded those of harpsichords, to the point that he ceased to manufacture harpsichords in 1793. He died in London.
Broadwood's other technical innovations in piano manufacture include:
As a company, Broadwood and Sons prospered, and was passed into the hands of his sons, James Shudi Broadwood and Thomas Broadwood. It is the oldest extant piano manufacturer in the world.
John marry Shudi's daughter Barbara in 1769. They had four children, then Barbara died. He then married Mary Kitson in 1781 and had a further six children. Many of his descendants were involved in pianoforte manufacturing in England and some were involved in the British Army in India during the reign of Queen Victoria. Others emigrated to Australia, where Broadwood descendants still live. The Broadwood family tree can be clearly traced back to circa 1580.
The British general Robert George Broadwood (1862-1917) was a grandson by his son Thomas (son by John's second wife Mary Kitson) and Mary Athlea Matthews.