Ayre D-1x DVD-Video/CD player
The degree of flexibility possible these days is illustrated perfectly by the D-1x. The base D-1x is a DVD-Video transport (sans DACs) priced at $5250. From that point, the range of available options verges on the dizzying: video only ($6000), audio only ($8000), audio and video ($8750), video only with VR2 progressive scan ($8750), or audio plus progressive-scan video ($11,500). My review sample was audio-only, but even there, things are not so simple. Optioned as a pure CD player, the Ayre plays back both 16/44.1 CDs and 24/96 DADs. Unlike some other DVD players, the D-1x also plays CD-Rs. About the only things you can't have are HDCD decoding and SACD playback.
The D-1x uses a Pioneer DVD-Video manufacturing kit, which comprises the transport, the display, the reomte control, and the MPEG decoder printed circuit board, which decompresses the DVD-Video data. Seven additional circuit boards are required before the D-1x performs all of the available functions at a level Charles Hansen finds acceptable. The motherboard distributes power and signals to the other PCBs, and an Ayre-designed master-clock board carries the audio DACs on a plug-in daughtercard, which provides the shortest possible path from master clock to DAC chips. Separate audio and videocards (for whatever configuration you've ordered) are also provided, as is an independent board handling all front-panel functions. Like its sibling, the Ayre K-1x preamplifier, the D-1x is accompanied by a sizable external power supply that contains 10 separate supplies to reduce modulation interference and provide the cleanest possible power to each independent section of the player.
What's on all of these PCBs is worth a close look. Ayre's proprietary solution to the eternal problem of clock jitter consists of a custom quartz oscillator to minimize phase noise; the clock signal itself is constructed entirely with single-gate devices, facilitating the use of individual, zero-feedback voltage regulators at each stage, resulting in the "eliminat[ion] of jitter-inducing modulation effects."
The D-1x's digital filter is a Burr-Brown DF1704. This 24-bit/96kHz-capable chip provides selectable filter algorithms, one of which provides flat frequency response through the audio passband (labeled Measure on the rear-panel switch), and another which, according to Ayre, offers "a mild rolloff in frequency response at the extreme upper end of the audioband, but offers significantly improved response in the time domain." This latter position is labeled Listen on the rear panel. (Switching between the algorithms had no effect on the digital audio output.) I never heard any lack of top end in the Listen position, and so did all of my auditioning in that mode.
Four specially selected Burr-Brown PCM1704K chips provide balanced digital-to-analog conversion. The DACs are capable of 8x oversampling conversion at 96kHz and 4x oversampling at 192kHz. Following D/A conversion, the audio signal is sent to a proprietary differential current-to-voltage converter, constructed with zero-feedback FET circuitry.
The power supply features individual transformers for audio and video/digital circuitry, and six isolated secondary windings are further subdivided into the 10 separate power-supply sections. The primary analog supply uses inductor-input filtering to eliminate transient charging currents to the filter capacitors, and several Ayre Conditioner noise filters are applied at strategic points to further reduce noise and interference on the power lines.
Like Ayre's K-1x preamplifier, on which I wrote a Follow-Up in the June 2002 issue, the D-1's significant upgrade to "x" status has come with no increase in price. As outlined above, the power supply has been a primary beneficiary of the upgrade, but the D-1x also includes major revisions to the ground-partitioning scheme. The individual grounds for the main chassis, power-supply chassis, AC mains, and transformer shielding have been optimized for maximum isolation from outside interference. And last but not least are the new, high-density polymer feet.