The American Magasine "The Minstrel Tempo" for January 1901 cvarries an advertisment for "Sonoro" guitars, mandolins,and banjos made by Chas F Alberts 205 S 9th Street, Philadelphia. Pa.  

 

Apart from a later reference to Alberts beinmg "Phila's Old Reliable Violin House"  we know no more.