Some players actually prefer these models, however, because they tend to compress more easily than any other Twin.
According to the dates on Fender schematics, these “improvements” only lasted for a year.
Master volumes are generally associated with and necessary in amps that use considerable front-end gain to overdrive the preamp section.
The signal level can then be reduced prior to the output stage to control overall amp volume.
Thanks, John Gilbert Matt Alcott Hi John, The Twin Reverb design has been through many iterations since its 1963 debut.