At the 12/24/1951 premier performance of 'Amahl and the Night Visitors', Amahl was played by 12 year old Chet Allen (born 5/6/1939) who also played Amahl in a live Easter telecast 4/13/1952. That summer, Chet Allen's voice changed and he was replaced with 10-year-old Bill McIver who played Amahl in the annual Christmas telecasts from 1952 through 1955 - McIver turned 13 a couple months before the 1955 telecast but still had his soprano range.
The Christmas telecasts of 'Amahl and the Night Visitors' in 1953 and 1954 were apparently in color, but the 2015 Video Artists International DVD containing a recording of the 1955 telecast is in black and white.