 All of these changes greatly simplified operation and made radio a household appliance that even a small child could operate, instead of the highly skilled hobbyists of the brief preceding generation.Reaction sets also had the filament adjustment rheostats for each valve, and again settings had to be right to achieve reception.In the era of early radio, only RCA and a select number of competing "prestige" radio manufacturers could afford to build a superheterodyne receiver (superhet).