Avarice User Manual

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 standalone 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.
DAC
DVD Player
S/PDIF out
S/PDIF in
Avarice
S/PDIF in
S/PDIF out
-2-
rev.1, January 2012
Avarice – User Manual
The Avarice version employing the optical input may serve as a highquality optical-to-metallic SPDIF converter (TOSLINK -> 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
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.
-3-
rev.1, January 2012
Avarice – User Manual
The effect of the jumper settings is also shown on a schematic on the
back panel.
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.
Input Fs
S1:OFF
Output Fs
S1:ON S2:OFF
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
88.2 kHz
88.2 kHz
88.2 kHz
176.4 kHz
96 kHz
96 kHz
96 kHz
192 kHz
176.4 kHz
176.4 kHz
176.4 kHz
176.4 kHz
192 kHz
192 kHz
192 kHz
192 kHz
S1:ON S2:ON
Fs – sampling frequency
-4-
rev.1, 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 by
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.
-5-
rev.1, January 2012
Avarice – User Manual
Specifications
S/PDIF input
•
protocol: S/PDIF (IEC958 / EIAJ CP1201)
•
type: coaxial, transformer-coupled, 75Ω impedance, BNC connector, optional
version equipped with TOSLINK input available on request
•
format: linear PCM stereo
•
supported sampling frequencies: 32/44.1/48/88.2/96/176.4/192kHz
•
supported bit depth: 16-24bit
S/PDIF output
•
protocol: S/PDIF (IEC958 / EIAJ CP1201)
•
type: coaxial, transformer-coupled, 75Ω impedance, BNC connector
•
format: linear PCM stereo
•
supported sampling frequencies: 32/44.1/48/88.2/96/176.4/192kHz
•
supported bit depth: 16 / 24bit
Jitter attenuation
•
recovery of the clock signal using digital PLL
•
two-stage re-clocking of the output SPDIF signal
•
three data-jitter attenuation modes
•
low-noise discrete regulators for the clock and the output circuits
HighHigh-quality synchronous upsampling
•
proprietary linear phase Zero Alias digital filters
•
33bit arithmetic / 67bit accumulator
•
2x and 4x upsampling performed in one single filter stage
User settings
•
Zero Alias LPCM Upsampling: on / off
•
Zero Alias LPCM Upsampling: 2x / 4x
•
output bit depth: 16 / 24bit
•
two user selectable upsampling filter characteristics
•
data jitter attenuation: off / mode 1-3
Power supply and dimensions
•
power supply connector: 2.1mm DC jack
•
voltage / current rating: 8-15VDC / 1A
•
lxwxh: 120x78x43mm
-6-
rev.1, January 2012
Download PDF