American Simplex; Amplex (United States) - AllCarIndex

American Simplex, later known as Amplex, was an automobile manufacturer based in Mishawaka, Indiana, active from 1906 to 1913. The company initially operated as the Simplex Motor Car Company, producing vehicles that featured 2-stroke engines. The first model introduced in 1906 was powered by a 40-horsepower twin engine, which was later upgraded to a 6.8-litre 30/50 horsepower four-cylinder engine by 1908. The cars were considered high-end, with prices reaching up to $5,400 for a landaulette model.

In 1910, the company rebranded to Amplex Motor Car Company to distinguish itself from the more prominent Simplex brand based in New York City. The Amplex lineup included a 40-horsepower 4-stroke poppet-valve six-cylinder model in 1913, and there were plans for a sleeve-valve engine variant, although it was never produced.

The company experienced a change in ownership during its final years, with notable figures such as William Wrigley, known for his chewing gum empire, acquiring Amplex in 1914. Wrigley sold the company two years later to William Gillette, a razor blade magnate, who contemplated the production of the sleeve-valve engine. Although a prototype may have been developed, Gillette ultimately shifted focus to selling the engine technology under the name Wilmo, a venture that lasted until 1917.