I was hoping there’d be some explanation of the preamplification being used, since ceramic cartridge output V is dependent upon stylus displacement not velocity. So ceramics don’t need RIAA filtering in the phono stage.
If you look at the RIAA curve, you’ll see a sort of ’flat’ spot that isn’t duplicated by the constant amplitude characteristic. So you do need some EQ. If you look at a proper ceramic phono input, you’ll usually see a network that takes care of this.
This is the same issue faced by strain gauge cartridges, although some of them are built to accommodate the RIAA curve.