|Downmix version only|
High resolution digital audio output module for OPPO BDP-93
The launch of Vanity - a high resolution digital audio output module - in 2006 enabled all audiophiles owning a stand-alone external digital to analogue converter to play back high resolution material in full digital quality. With the onset of the Blu-ray format, developments of digital home theatre and the spread of multi-channel recordings, it was becoming ever more apparent that a good signal source for fully digital multi-channel amplifiers and high-end rigs was absent on the market.
This has been true - up to now!
The Vanity93 continues the product range started by its two-channel predecessor designed for universal DVD players. It enables to turn the OPPO BDP-93 player into an eight-channel high-end digital transport. This player is highly praised for its versatility, reliability and ease of upgrading its output circuit boards. The Vanity93 is an add-on module that can simply replace the analogue output circuit boards of the BDP-93 with full resolution digital outputs.
The Design in Details
The Vanity93 module is designed as an upgrade to be installed into the Oppo BDP-93 universal player. It provides digital outputs carrying up to eight channels of full resolution audio data via standard S/PDIF, and supports all audio formats including Blu-Ray, SACD and DVD-A.
The original analogue outputs on RCA connector block are replaced by digital outputs. As the S/PDIF signal is two-channel, 4 of the total of 8 RCA connectors in the lower of the two connector rows remain active with the Vanity93. The mapping of digital output channels therefore corresponds to the diagram on the player's rear panel.
The output is transformer-coupled, at 75R impedance. The signal passes a digital re-clocking stage in order to achieve maximum noise attenuation and prevent interference with internal signal-processing circuits of the player. The entire output circuit is powered from a discrete low-noise regulator. The maximum sampling frequency on the output is 192 kHz, with 24 bit maximum word length.
In universal players, the internal circuitry is always designed mainly with the video signal in mind. Sampling frequencies for the audio signals are usually derived in a complicated manner from the video clock signal. Their stability is far from ideal, this results in an audible degradation of sound by so called "jitter". To redress this flaw, Vanity93 employs its own digital PLL techniques and low-noise 'pullable' oscillators, whereby the data is perfectly de-coupled form the clock source of the player and a precise dedicated clock signal is used to provide timing of the output signal.
Data from the player is stored in a buffer memory. The utilisation of the buffer memory controls the frequency of a local voltage-controlled oscillator to ensure that the buffer memory is utilised in an optimal manner. This method allows the synchronization of both time domains. The adaptive algorithm of controlling the local oscillator adjusts the frequency with delays between individual frequency corrections satisfactorily long and they can reach dozens of seconds. The oscillator is adjusted by a discrete R2R DA converter, powered ' just like the oscillator - by a discrete low-noise voltage regulator.
DSD to LPCM Conversion
In 'raw DSD' mode it supports digital playback of SACD media in the highest 24bit, 88.2/176.4kHz quality both for stereo, and for all 6 channels of multi-channel layer. The widely used 4.0 speaker configuration is covered by the dedicated down-mix algorithm implemented in the Vanity93 module. For multi-channel systems using other than 5+1 and 4+0 loudspeakers, the multi-channel material downmix for any speaker configuration is provided by a DSD to LPCM conversion within the player. Key parameters of the conversion, such as output sample rate, bit depth and filter characteristics are user-configurable.