It depends on a number of equipment-dependent variables, including the output impedances of the phono stage and preamp, other aspects of the designs of the output stages of those components (which may be unknown), the capacitance of the particular cable, and possibly the susceptibility of the components to ground loop issues (which is usually unpredictable). Let us know the make and model of the phono stage and the preamp, and we **might** be able to make a prediction.
Regards,
-- Al
Regards,
-- Al