I didn't know the make of the sousaphone or mouthpiece then, I didn't care!!
Upon reflection they seemed to be King fiberglass sousaphones, in a Wenger chair and a Bach 24AW.
This lasted until High School. (77-80) There I had a Conn 20J (We called her Betty) for concert band. I preferred the funnel shaped Conn#2 mouthpiece to the Bach 18s we had. That was what we got. It never occurred to me to buy my own mouthpiece or tuba. We did get two shiny new concert tubas. I don't know their make but they had thin metal and made a tinny sound that I didn't like.
I was really into band. I took up the upright bass along with tuba in 5th grade, but stopped after 9th grade. The orchestra didn't travel or do half time shows!!
