Overview:GTI was established by K.C. Retzlaff in 1948. It was operated as a proprietorship under the name of Precision Transformer located in Muskegon, Michigan, USA. In 1951, the company was moved to Grand Haven, Michigan and incorporated under the name Grand Transformers Incorporated. As a result of K.C.'s love for amateur radio and his interest in electrical "tinkering," GTI has grown to become a 'World Class Manufacturer' of inductive components. In 1956, construction was started at the present Marion Street site. Over the years, there have been numerous expansions to support the company's growth. 1973 brought in a change in management as K.C.'s two sons, Gerald and Gregory, purchased the company prior to the founder's retirement.