SIGMA GUITARS Catalog # Guitar Catalog Related Sigma Guitars is a guitar manufacturing brand launched by C.F. Martin & Company as an affordable guitar series to counter the increase in imported guitars from Japan and other countries. The Sigma series was discontinued by Martin in 2007. Later, AMI Musical Instruments GmbH of Germany acquired the brand name and revived the brand by manufacturing guitars in China. #SIGMA #SIGMAGUITARS #Guitar #Acoustic Guitar #GUITAR