I can assure you that the plinth of pioneer PL70 (I assume it is the same for Pioneer PL70II) even if very heavy it is entirely in wood chipboard, do you know how the box speakers were built in the 70s / 80s? Here it is the same, perhaps it is high density wood chipboard but always chipboard is, while the top coating is real wood veneer.
The Technics SH10-B3 plinth consists of the lower base in real wood (multilayer), a central layer of double rubber and the upper top in obsidian, but I who have disassembled everything I say that there is obsidian powder, glue and cement, everything poured into a mold and then painted in piano black.
From the my Technics SH 10B3 base I can safely put photos
https://i.postimg.cc/tCnJXZV9/P1000547.jpghttps://i.postimg.cc/zvbzX6vx/DSCN6111.jpghttps://i.postimg.cc/cCpsKh80/DSCN6113.jpghttps://i.postimg.cc/sXzH2h2q/P1000551.jpgcompressed wood dust (MDF) is better than the chipboard of the past but it is disastrous to build turntable plinths, it has the advantage of being very cheap, compact and easy to work with very precise cuts, but it is too deaf a material, contraindicated to make plinths of turntables.