08-28-2021, 06:15 PM
I think I might be able to answer the question for the dead Philco engineers.
A similar feature did exist on many record players in 50-s, 16 rpm, half of the 33-1/2.
It was also used for playing 16-2/3 rpm records but those never became to popular and were used for radio. mostly spoken programming.
But they also gained the name of "transcription" players ad at exactly half speed they would allow playing the record at exactly the same key at half speed, which was convenient for transcribing music into notes in bands.
Perhaps 39, being exactly 1/2 of 78, could be used for the same purpose when 33-1/2 speed was not yet conceived.
A similar feature did exist on many record players in 50-s, 16 rpm, half of the 33-1/2.
It was also used for playing 16-2/3 rpm records but those never became to popular and were used for radio. mostly spoken programming.
But they also gained the name of "transcription" players ad at exactly half speed they would allow playing the record at exactly the same key at half speed, which was convenient for transcribing music into notes in bands.
Perhaps 39, being exactly 1/2 of 78, could be used for the same purpose when 33-1/2 speed was not yet conceived.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.