Dell does not officially support sound cards in PowerEdge Servers. However,
PCI slots in the 1600SC are as follows:
two 32-bit 33MHz PCI slots, suitable for pcHDTV HD-3000 ATSC capture card and nVidia 5200 video card (for example).
two 64-bit 66MHz PCI slots, suitable for SCSI cards like the Adaptec 39160 or the Adaptec 3950 which work reliably.
two 64-bit 100MHz PCI-X slots (which support 3.3V or universal cards), suitable for a Creative Labs Audigy2 sound card, for example.
Just make sure you use a 3.3V Sound Card.