Not sure, it was either Uriah Heep "Demons and Wizards" or Wishbone Ash "Argus".
I'd only heard classical music and the Beatles, so when other kids brought albums by Deep Purple and Led Zeppelin into school, to begin with many of the tracks just sounded like noise to me. Although Led Zep Since I've been Loving You and Black Dog made quite an impression.
Heep and Wishbone were more melodic, at least that's how I remember it.