When I started playing guitar it was 1984. If your amp didn’t have a good distorted sound, you could get a good distortion pedal to get that Randy Rhoads type sound. So this isn’t based on my personal experience, but mostly on what I’ve read about it including interviews.
I’ve read interviews in some of the major guitar magazines with well known shred guitarists who have said they can play fast with a completely clean sound or with a good distorted sound, but not with that in between half-distorted Jimmy Page sound. Well, that “half-distorted sound” is pretty much all you could get in the early and mid 70s, as far as I know. Even Judas Priest, who have become synonymous with heavy metal had a much less distorted tone on their 70s albums than on their 80s albums. Compare their tone on “The Sinner” from their Sin After Sin album to their tone on “The Sentinel” from their Defenders Of The Faith album. There’s a lot more gain on The Sentinel and it’s because that sound was available to them in 1984. That tone wasn’t available to them on 1977 when Sin After Sin was released.
So if you look back to the fast guitarists according to the standard of the day, the state of the art for shredding really took off at around the same time that it became possible to get a high gain guitar sound which adds compression as well as distortion and makes shred playing easier to do.
Do any of you find that it is just as easy to shred with a mid 1970s Jimmy Page type distortion as it is with the more high gain sound which to the best of my knowledge first appeared on the album Van Halen which was late 1970s and at the time was a tone which wasn’t widely available to guitarists?
Here’s The Sinner by Judas Priest and is a good representation of what their guitar tone was back then. They were one of the heaviest bands around. There weren’t many or any bands as far as I know back then playing with a more distorted sound.
Now here is the same band from their 1984 Defenders Of The Faith album. notice how much more heavily distorted the guitar sound is here.