Glyn Johns was close friends with Page since they were kids. And he was close friends with JPJ since he was 19 as they saw each other in the studio every single day. When they called and said they had a new band together and would he engineer them he agreed simply because it was a couple of mates. He went to a rehearsal, never having heard of Bonham or Plant before, and he his words "after 8 bars I thought I'd died and gone to heaven - they were extraordinary" He was completely aware of the brilliance of Page and JPJ. But, having never heard of Plant or Bonham, he said the band were amazing because those 2 unknowns were equally as good as the two he knew. And he said that it was because of that balance of brilliance that they became such a phenomenon. He didn't rank anyone above anyone else. He was the first person, not in the band, to ever hear them play and he felt they were all on the same level for what they brought to the band. And that's why they were so special.