The 100 ohm value suggests that your preamp is unhappy with RFI (Radio Frequency Interference) at its input.
The 100 ohm value detunes the RF circuit caused by the tone arm interconnect cable and the inductance of the cartridge. As a consequence, the optimal loading value varies from cable to cable. Of course, if your preamp is stable with RFI at its input, the loading value will cease to be a concern.
The 100 ohm value detunes the RF circuit caused by the tone arm interconnect cable and the inductance of the cartridge. As a consequence, the optimal loading value varies from cable to cable. Of course, if your preamp is stable with RFI at its input, the loading value will cease to be a concern.