Just like a many manufacturing of environments back in the day, vinyl stampers were used well beyond their lifespan. Stamping machines were not properly adjusted, maintained at required intervals. It was all about pushing product out the door and not slowing production. Close to shift change? "Keep the presses moving along...I’m not taking the changeover hit on my shift". People talk about unmotivated and downright lazy practices by US automotive employees back in the day? Same thing at record pressing plants (and other industries). The 70’s (well into 80’s and 90’s) was an all time low for quality work practices in all of US manufacturing. Vinyl record production was no different. Mastering is a major part of an LP's sound, however, poor manufacturing practices and materials can kill any sonic advantages of vinyl. First pressings done closest to release date are probably the best you will find (outside of some audiophile version) IMO.
