M700 vs S300 Input Stage Differences

Have a question reviewing the circuits between these two Stellar amps. While the input modules of both state they are direct coupled and appear to be the same potted module, the M700 has two 1uf Rel-Caps which are not present on the S300. Does anyone know their function as their quality would indicate that they are in the signal path which would eliminate the direct coupling to the amp modules?