NAD Unveils New Surround Sound A/V Receiver For Music-Oriented Home Theatre

8-Sep-00

NAD introduces its Theatre Series T751 DolbyÆ Digital/DTSÆ Digital Surroundô A/V receiver. The T751 is said to be part of a virtually new product category - the music-first A/V receiver, and is introduced at the CEDIA EXPO 2000 in Indianapolis, Indiana.The T751 A/V Receiver is the successor to NADís T750. The T751 is claimed to offer significant performance upgrades over its predecessor, with better connectivity options and enhanced convenience features. The T751 uses an integral Dolby Digital/DTS Digital Surround decoder and Crystal Sigma-Delta DACs with 96kHz/24-bit resolution. Equipped with discrete power-output stages, the T751 is rated to deliver 60 watts continuously into all five channels simultaneously at no more than 0.08 percent THD. ""We examined popular A/V receivers and found no shortage of elaborate features or seemingly impressive power ratings,"" said Greg Stidsen, NAD Director of Sales and Marketing. ""But almost without exception, the existing designs failed to get the fundamentals right,"" Stidsen continued. ""By overlooking the central importance of intrinsic sound quality - in favor of feature content - virtually all popular A/V receivers fail to fully serve the primary function of any high-fidelity sound system, which is the simple enjoyment of music listening.""For the T751, NAD says that the engineers chose the best available (within the budget) - Crystal Sigma-Delta ADCs and DACs, each with 96kHz/24-bit resolution. The DSP chip that decodes Dolby Digital, DTS Digital Surround, Dolby Pro Logic (in the digital domain) and NADís EARS ambience modes is also from Crystal.The T751 shares many underlying engineering principles with other NAD receivers and amps. The amplifier design relies on substantial, highly dynamic power supplies and fully discrete-component output-stage topologies for all five channels.The T751ís power output, at 60 watts per channel, seems unexceptional, but NAD claims that the receiver was rigorously engineered for the demanding, reactive loads imposed by typical loudspeakers, with power output capability of as much as 225 watts into 2 ohms, and peak current capability of up to 40 amps. NAD attributes this performance to a new Impedance Sensing Circuitry (ISC) power supply designed by Bjorn Erik Edvardsen. ISC automatically recognizes the impedance characteristics of connected speakers and adjusts the receiver's internal power supply to deliver the optimal ratio of usable voltage and current - in a word, power - to that particular load.The T751ís tuner circuit is said to balance the need for high sensitivity (for distant FM signals) with the need for a highly discriminatory capability to select among the strong, closely spaced signals that crowd metropolitan area FM bands.The T751 also incorporates NADís Enhanced Ambience Recovery System (EARS). This system supposedly extracts the ambient information ""encrypted"" in virtually all stereo recordings - especially natural-acoustic music discs in jazz, classical and folk genres.The T751 includes five video inputs (three with S-Video), two video outputs (one with S-Video), plus two audio-only options and three digital inputs - two RCA coaxial and one Toslink. A separate 5.1-channel analog input permits future expansion via an external processor. Preamp outputs for all five channels are also available, along with 30 tuner presets.The suggested retail price for the T571 is $749.

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