The peak popularity of the electric guitar brought a call for amplification equipment, (which was demanded also for voice amplification, together with microphones and control gear). The Rose Morris of old had steered clear of electrical apparatus, but the new Rose-Morris had no such inhibitions, and the importation of some popular American-built amplifiers began.
Electronic organs were also imported, but in small quantities: at that time RM lacked the specialised 'know-how', and the market was small and ill-defined. Amplifiers from British manufacturers were then handled, with a fair degree of success, but performers were never entirely satisfied - the 'sound' wasn't right: yet nobody seemed able to define exactly what was needed.
One of the company's customers, feeling the need and sensing the nature of the requirements and being unable to obtain anywhere the equipment required, set about designing and making it. The sound was right: the answer had been found. The customer was, of course, Jim Marshall - and from his small beginnings as a manufacturer grew the considerable industry now producing the famous Marshall Amplifiers, renowned all over the world.
Jim Marshall knew what was wanted, and produced it. His sales experience, particularly of wholesaling and exporting, did not extend to a marketing exercise of the magnitude necessary to exploit his product. A friendly agreement was negotiated with Rose-Morris, whereby RM would enjoy worldwide sole sale and would undertake the promotion and distribution of the output of the Marshall factory. In its history RM has negotiated a number of similar friendly arrangements with manufacturers, and it is a subject of some pride that the outcome has been to mutual benefit, with willing and amicable co-operation on both sides.