Q: Is it possible to operate a USBPre 1.5 without interfacing or connecting it to a computer (i.e. passing a 16 bit/48 kHz digital signal to a DAT deck via SPDIF)?

A: The USBPre 1.5 requires a computer to operate. There is no provision for external operation in absence of a computer. Think of the USBPre as an external sound card, with its input routed to the computer and its output fed from the computer. The USBPre 2, on the other hand is capable of operating in stand-alone mode (Not connected to a computer).