The sub chassis has changed quite a lot.
The first couple of thousand or so LP12s from 73 to 74 had a dual ribbed sub chassis with a cross rib.
They then dropped the cross rib.
Fairly quickly after that came the welded strengthening strap John is referring to and then eventually the bonded strengthening strap version.
After that came the Cirkus version and eventually Magik, Kore and Keel.
The outer platter has changed at least 3 times. From 73 to around 76 these were about 0.6kg heavier than modern outer platters so different centre of gravity.
The inner platter has also changed at least 3 times with early ones having a longer spindle and ride height. Modern outer platters do not fit the early inner platters.
The first couple of thousand or so LP12s from 73 to 74 had a dual ribbed sub chassis with a cross rib.
They then dropped the cross rib.
Fairly quickly after that came the welded strengthening strap John is referring to and then eventually the bonded strengthening strap version.
After that came the Cirkus version and eventually Magik, Kore and Keel.
The outer platter has changed at least 3 times. From 73 to around 76 these were about 0.6kg heavier than modern outer platters so different centre of gravity.
The inner platter has also changed at least 3 times with early ones having a longer spindle and ride height. Modern outer platters do not fit the early inner platters.