Above is the plot of Micro Seiki RX-1500G
playing back a 3150 Hz track on a Dr Feickert test LP
. The green trace was obtained by using a Sumiko Pearl
cartridge, and the green one with an Audio Technica AT11E
And while there are quite prominent sidebands on the green trace, the red one is quite different. As I long suspected, these are the result of the playback (or recording) chain imperfections.
This doesn't mean that all such sidebands originate in the pickup or downstream of it. But in my opinion, it's impossible to reliably separate the influence of the drive from that of the playback chain.