Adcom GTP-760: Multi-source, Multi-format Champ

Continuing its tradition of high-value products, Adcom has introduced the GTP-760, a tuner/preamp made with home theater fans in mind. Its ability to handle DVD-Audio discs in either 5.1 channel surround sound mode or traditional two-channel stereo mode will attract music lovers, too. Movie soundtracks can be decoded by the GTP-760 in both DTS and Dolby Digital formats.

Building on their experience with Adcom's acclaimed GDA-600 and GDA-700 digital-to-analog converters, the company's engineers have devoted substantial energy to maintaining linearity throughout the digital signal path. All analog inputs to the GTP-760 are converted to digital for processing by three Motorola 24-bit digital signal processors (DSPs) each capable of more than 100 million instructions per second ("MIPs"). Such processing allows two-channel sources to be converted to surround sound without the typical degradation that occurs in most derived surround conversions.

The GTP-760 works as an outboard DAC with CD transports or CD/DVD-V players equipped with digital outputs. Processing of DVD-A signals is via the analog outputs of DVD-A players. (Music industry copyright concerns have limited the digital output of the new players to the CD standard 44.1kHz sampling rate.)

Movie surround modes include DTS, Dolby Digital (AC-3), Digital Dolby Pro-Logic and Cinema Pro-Logic. A Digital Bass Management (DBM) feature is said to improve low frequency coherence in Dolby Digital and DTS modes. A "Cinema" feature equalizes the front three channels and adds calculated delays to the rear speakers to achieve the sound of a large theater---an effect said to be especially appropriate for older soundtracks recorded before the 5.1 system became an industry standard. There are also other programmed acoustic affects to replicate the sounds of music venues ranging from small clubs to large stadiums. Adcom claims that opera discs are especially enjoyable with the processors set to "Symphony Hall" mode. Of course, the GTP-760 can be used in two-channel mode for excellent reproduction of most music.

With real-world users in mind, Adcom has included a Dynamic Range Control that allows soft dialog to be boosted for clarity while keeping big sonic effects under control, a feature that may preserve domestic and neighborly relations. Design enhancements include military-spec fiberglass circuit boards, an oversize power supply for minimum noise, precision parts for signal linearity, and nine independent levels of DC regulation to guarantee maximum fidelity regardless of source. A "Room 2" feature lets you use the GTP-760 as a router for a separate system in another part of the house. With nine audio inputs (six analog and three digital) and six video inputs (including S-Video) the GTP-760 is ready to meet any challenge.

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