How much of a problem the capacitance of an RCA extension would cause, if any, depends on the particular cartridge. Let us know what that is. Hopefully its manufacturer provides a recommended load capacitance range.
Also, the input capacitance of the phono stage in your AV7704 adds to the load capacitance that is seen by the cartridge. Unfortunately the documentation on the AV7704 doesn’t specify what that input capacitance is. You might want to contact Marantz and see if they can provide you with that information.
Without having a load capacitance recommendation for the particular cartridge, and without having some idea of the input capacitance of the phono stage of the AV7704, unfortunately the answer to your question has no predictability. And for all we know, depending on those variables the added capacitance of an extension might actually improve sonics, rather than compromising them.
Regards,
-- Al
Also, the input capacitance of the phono stage in your AV7704 adds to the load capacitance that is seen by the cartridge. Unfortunately the documentation on the AV7704 doesn’t specify what that input capacitance is. You might want to contact Marantz and see if they can provide you with that information.
Without having a load capacitance recommendation for the particular cartridge, and without having some idea of the input capacitance of the phono stage of the AV7704, unfortunately the answer to your question has no predictability. And for all we know, depending on those variables the added capacitance of an extension might actually improve sonics, rather than compromising them.
Regards,
-- Al