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EVO PHONODAC TWO
DXD-DSD A-TO-D AND D-TO-A CONVERTER – PHONO PREAMP
REVISION P
R
A – JULY 2016
Copyright © 2016, M2Tech Srl
20
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bypass their deck head amp. See Chapter 9 for more details. Of course, a “flat” setting (no
equalization) is available for all uses different from record ripping or playback.
7.5. Clip indicator
As the
EVO PHONODAC TWO
input headroom is, like every ADC, limited, a clip indicator is
provided (Fig. 1, 2). The clip indicator lits whenever the input signal is larger than a preset
reference level. This indicator is useful to correctly set the analog input gain. A more
refined setting can be achieved by using the level indicators of the program used to record
on the computer from the
EVO PHONODAC TWO
. Setting the reference value to -6dB or
similar minimizes the risk of clipping the signal during conversion, at the cost of around
1bit resolution. Setting the reference value to -2dB to 0dB allows to fully exploit the ADC
dynamic, at the cost of more likely clipping events. When using the
EVO PHONODAC TWO
as a phono preamplifier, a few clipping events can be tolerated, as they’re most probably
related to clicks and pops due to record surface dirt or damages.
7.6. External clock, auxiliary S/PDIF input
The
EVO PHONODAC TWO
is provided with an input for an external clock (Fig. 2, 6). This
input is very versatile, as it’s able to recognize the frequency of the clock applied and,
when needed, synthesize the needed master clock.
The external clock input accepts all most common word clocks and the so-called “super
clock” plus, of course the master clocks generated by the
Evo CLOCK Two
. Moreover, it
accepts the 10MHz standard reference clock.
The external clock input can be disabled, or enabled in automatic mode: in this mode,
when a valid clock is detected on the external clock input, it is used to clock the unit,
otherwise the
EVO PHONODAC TWO
automatically reverts to the internal oscillators.
Together with the external clock input, the
EVO PHONODAC TWO
is provided with an optical
output by means of which it sends the
Evo CLOCK Two
information about the needed
sampling frequency. This way, the
Evo CLOCK Two
is able to automatically switch the
clock based on the
EVO PHONODAC TWO
requirements, without the use being asked to
manually operate it.
When the
PHONODAC TWO
external clock input is disabled, it can be used as a digital input
in S/PDIF format. It accepts PCM digital audio 44.1kHz to 192kHz. As most digital audio
sources are provided with an RCA connector, while the
PHONODAC TWO
input is provided
with a BNC connector, a special digital interconnect fitted with RCA plug on one side and
BNC plug on the other wide may be necessary. As an alternative, user may apply an RCA-
to BNC adaptor (RCA female, BNC male) to the
PHONODAC TWO
input and use a normal
RCA-terminated digital interconnect. On the other hand, sources provided with BNC output
connector may be connected using a BNC-terminated digital interconnect.