This processor/preamp has a high interest quotient because, like its predecessor, the Bryston SP 1, the SP 1.7 can operate in two modes: "digital" and "bypass." The first provides decoding for all home-theater technologies: Dolby Digital, Dolby Pro Logic, DTS-ES Discrete 6.1, DTS-ES Matrix 6.1, DTS Neo:6, THX Surround EX, THX Ultra certified, as well as PCM (32, 44.1, 48, & 96 kHz) through 24-bit converters. In contrast, "bypass" mode turns the SP 1.7 into a purist analog preamplifier (the technical equivalent of the Bryston BP-25 stereo preamp), intended for high-quality, discrete amplification of stereo analog inputs.