The D'Addario brand is best known for its range of instrument strings and Planet Waves guitar accessories - but it also produces percussion and woodwind accessories. The D'Addario company was founded by Rocco and Charles D’Addario who came from a family of farmers and string makers. The D'Addarios emigrated from Italy to Astoria, Queens, New York after an earthquake destroyed their home town of Salle in 1905.

Peterson have been in the tuning business since the 1950s. They have traditionally specialised in high precision mechanical strobe tuners but have also developed a range of virtual software based tuners. Some of their tuners featured "sweetened" tuning which offers sets of optimized tuning offsets designed with a particular instrument in mind to help combat the bland tone equal temperament tuning provides.

C. G. Conn Ltd. was a musical instrument company founded in 1874 in Elkhart, Indiana. They manufactured a full line of band instruments including wind, strings and percussion. They also manufactured organs, pianos and music boxes. Conn did not manufacture their own guitars but distributed both American made and imported guitars, banjos and zithers.  In 1969 Conn was sold to the Crowell-Collier Macmillan Company (who were primarily publishers) and the Conn guitar division was established in Oak Brooks, Illinois. The Conn guitar division contracted Tokai Gakki in Japan to make a range of acoustic guitars - and these were available until 1979. Conn also entered the electric guitar market with a series of original designs and some copies but Conn discontinued their electric guitar line by mid-1980, and the company was sold again. In 1985 the Conn Strobotuner division was bought by Peterson Electro-Musical Products, who continue to service Conn products.