Similarity between the Neumann U47 amplifier and early hearing aid amplifiers

For example comparing typical 3 stage electron tube amplifiers in class A (electrons flowing all the time):


http://euroelectron.blogspot.com/2018/08/more-nice-hearing-aid-schematics.html


and the classic Neumann U47 with the VF14 one electron tube amplifier:


http://downloads.bbc.co.uk/rd/pubs/reports/1954-23.pdf