As someone who is both an electrical engineer and an audiophile, I don't see any problems with respect to either of your two questions.
If both the cable capacitance and the preamp output impedance were unusually high, there could be a slight upper treble roll-off which would become unequal between the two channels if the cable lengths were unequal. But I very much doubt that is the case, especially for a run of only 10 feet.
Regards,
-- Al
If both the cable capacitance and the preamp output impedance were unusually high, there could be a slight upper treble roll-off which would become unequal between the two channels if the cable lengths were unequal. But I very much doubt that is the case, especially for a run of only 10 feet.
Regards,
-- Al