Ella Fitzgerald explained it all some years ago:

I press the little switch here

Electrons go 'round and around

Whoa-ho-ho-ho-ho-an'

Music comes out here

I press that valve amp switch

Electrons go down and around

Whoa-ho-ho-ho-ho-an'

Music comes out here

I lower that tone arm down

The record goes round and sound bellows

Bellows, bellows, deedle-dee-ho-ho-ho

Listen to the PRaT come out

I push the loud knob down

Electrons go 'round and around

Whoa-ho-ho-ho-an'-mo'

Music comes out here