Avarice User Manual
Contents
1. QUCIOpr alse AVARICE User Manual Avarice User Manual Introduction The Avarice is a device primarily aimed at the owners of digital to analog converters digital amplifiers digital crossovers and other devices which perform digital to analogue conversion and therefore rely on a high quality of the incoming digital signal The Avarice helps to attenuate and reject all sorts of interference between various devices to restore the time domain of the S PDIF signal i e to attenuate jitter and to upsample the signal up to four times thus bypassing the imperfect digital filters present in any integrated DAC chip Connecting the Avarice into the signal path and setting its signal processing parameters is very simple and intuitive Connection The device has one input and one output and can therefore be simply introduced into the S PDIF signal path by placing it between the signal source and the signal receiver Typical signal sources include CD DVD players satellite or cable TV receivers multimedia players PC sound cards portable music players etc Signal receivers performing DA conversion include stand alone DA converters AV receivers digital amplifiers digital crossovers and the like The diagram below shows an example of a signal path employing the Avarice Suitable S PDIF cables terminated by BNC connectors can be included in the packaging of the Avarice on the customer s request DVD Player iy me poe O2. back panel 712345 6 ON gt Nn _y mee Switch 1 enables ON or disables the upsampling function Switch 2 upsampling to 96 kHz or 192 kHz ON Switch 3 output bit depth value set to 16 bit or 24 bit ON Switch 4 digital filter characteristic 1 ON or 2 Switches 5 and 6 compatibility setting of the S PDIF output Switch 1 activates 2x or 4x upsampling performed in a single filtering Stage If this switch is set to the OFF position the Avarice does not alter the audio data the position of switches 2 and 4 has no effect in this case Whenever switch 1 is at the ON position the position of switch 2 determines if two or four fold upsampling is performed according to the maximum output sampling frequency Switch 4 allows the user to select one of two available digital filter characteristics The following table contains the input and output sampling frequencies and the corresponding switch settings Output Fs S1 OFF S1 ON S2 OFF S1 ON S2 ON 32 kHz 32 kHz 32 kHz 32 kHz 44 1 kHz 44 1 kHz 88 2 kHz 176 4 kHz 48 kHz 48 kHz 96 kHz 192 kHz Fs sampling frequency rev l January 2012 Avarice User Manual Switch 3 determining output bit depth is active at all times It is useful mainly for the owners of so called non oversampling DACs or older devices which usually employ a 16 bit word length The setting of this switch to 16 bits will ensure correct bit depth reduction of a 24 bit input signal b
3. O S PDIF out S PDIF in Avarice S PDIF in S PDIF out rev l January 2012 Avarice User Manual The Avarice version employing the optical input may serve as a high quality optical to metallic SPDIF converter TOSLINK gt S PDIF The Improvement delivered by the Avarice can be particularly significant when used to connect an optical signal source which is more susceptible to jitter The Avarice can be fed with power by the supplied universal power source or by any other DC source meeting the required parameters see specification sheet LED indicators The current operational mode of the device is indicated by four diodes located on the front panel The LEDs light up individually or in various combinations to indicate the input sampling frequency ranging from 32kHz to 192kHz as shown on a schematic printed on the back panel of the device If no input signal is detected all four diodes light up and become slightly dimmed after some 30 seconds so that the device does not visually disturb the room interior Settings Various audio signal processing parameters can be user configured using six jumpers accessible from the front panel Jitter attenuation is active at al times for all input sampling frequencies It is a result of the choice of circuit topology and cannot be deactivated by the user rev l January 2012 Avarice User Manual The effect of the jumper settings is also shown on a schematic on the
4. he clock and the output circuits High quality synchronous upsampling e proprietary linear phase Zero Alias digital filters e 33bit arithmetic 67bit accumulator e 2x and 4x upsampling performed in one single filter stage User settings e Zero Alias LPCM Upsampling on off e Zero Alias LPCM Upsampling 2x 4x e output bit depth 16 24bit e two user selectable upsampling filter characteristics e data jitter attenuation off mode 1 3 Power supply and dimensions e power supply connector 2 1mm DC jack e voltage current rating 8 15VDC 1A e Ixwxh 120x78x43mm rev l January 2012
5. y applying TPDF dithering Switches 5 and 6 enable the user to modify the structure and certain synchronization elements of the S PDIF protocol which can have an impact on sound so called data jitter Four setting configurations are available in total as some S PDIF receivers may not work with some of the available settings The setting combinations have to be tested by trial and error With both switches in the OFF position up the output is set to a standard format compatible with all receivers Should you have any questions or concerns you can contact our dealers Alternatively please contact us on ap audiopraise com rev l January 2012 Avarice User Manual Specifications S PDIF input e protocol S PDIF IEC958 EIAJ CP1201 e type coaxial transformer coupled 750 impedance BNC connector optional version equipped with TOSLINK input available on request e format linear PCM stereo e supported sampling frequencies 32 44 1 48 88 2 96 176 4 192kHz e supported bit depth 16 24bit S PDIF output e protocol S PDIF IEC958 EIAJ CP1201 e type coaxial transformer coupled 750 impedance BNC connector e format linear PCM stereo e supported sampling frequencies 32 44 1 48 88 2 96 176 4 192kHz e supported bit depth 16 24bit Jitter attenuation e recovery of the clock signal using digital PLL e two stage re clocking of the output SPDIF signal e three data jitter attenuation modes e low noise discrete regulators for t
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