.. was born in Islington, London in 1875 and his father who was a banjoist taught his son, James Charles, to play the instrument at an early age.

By 1897  J C Bertolle was playing duets in public with another banjo player named Heght and a year later organised a banjo club from his pupils. By then he had become a professional photographer with studios at 268 Caledonian Road, London, but managed to give between 30 and 40 banjo lessons every week.

In 1898 he formed a playing partnership with Gordan Tait, calling themselves "The Dexters," made their concert debut at a Cammeyer concert.

Within a short time they had played at most of the concert halls within fifty miles of London. They were hailed as the "British Mays and Hunter." The instruments they played were "Dexter" banjos sold exclusively by Bertolle who, in his advertisements said he made them - but this is doubtful. It has been found impossible to discover who made the high grade banjos but it could have been Richard Spencer as they have all the features of the early Spencer instruments.

No "Dexter" banjos appear to have been sold after about 1930.

Note: Bertolle also sold the "B&T"  model (Bertolle & Tait), almost certainly made by Clifford Essex staff.  Note the bracket nuts inside the pot which are identical to the CE "Imperial" model of the same period .. however it does have the "Spencer" style laminated neck. Similarly the Tester