Micromega CD 10 MM CD10SILVER User Manual
Product codes
MM CD10SILVER
The drive mechanism
The MICROMEGA team’s wish was to be innovative in this field and to use a DVD mechanism; this was
for very good reasons. Due to the success of DVD, DVD mechanisms produced today are of top, reliable
quality, simply because they are mass produced and therefore subject to extremely tough quality control
procedures inherent to mass production. It is for this reason that we took the wise decision to equip the
CD10 with the latest generation SONY KHM313 or SANYO SFH850 DVD mechanism. The mechanism
control is ensured by a Philips SAA78247 circuit and a MICROMEGA proprietary software program
featuring error correction algorithms which are particularly efficient and designed for audio reproduction. At
present and in many cases, CD players are optimized to read CD ROM. Indeed, audio CD is read at
nominal speed, whereas in the case of CD ROM, some players reach up to 52 times nominal speed. It’s a
different aspect but it is not the most significant. When reading CD ROM, it is possible, if a batch of data
contains errors, to go back and to re-read the passage, before choosing the best remaining error
interpolation strategy. This solution is absolutely unthinkable in audio terms, because in the event of errors
the aim is to privilege continuity of the musical message so that the listener doesn’t realize that the player
is correcting inaccurate data. Obviously, it’s impossible to stop the reading and to repeat a passage
several times to remove a scratch, a finger mark or anything else which could have triggered the error
correction system. In light of this, we can see how important it is to adopt a specific strategy to audio
reading and why the MICROMEGA team invested so much energy and time into developing the most
appropriate solution in terms of musical reproduction.
for very good reasons. Due to the success of DVD, DVD mechanisms produced today are of top, reliable
quality, simply because they are mass produced and therefore subject to extremely tough quality control
procedures inherent to mass production. It is for this reason that we took the wise decision to equip the
CD10 with the latest generation SONY KHM313 or SANYO SFH850 DVD mechanism. The mechanism
control is ensured by a Philips SAA78247 circuit and a MICROMEGA proprietary software program
featuring error correction algorithms which are particularly efficient and designed for audio reproduction. At
present and in many cases, CD players are optimized to read CD ROM. Indeed, audio CD is read at
nominal speed, whereas in the case of CD ROM, some players reach up to 52 times nominal speed. It’s a
different aspect but it is not the most significant. When reading CD ROM, it is possible, if a batch of data
contains errors, to go back and to re-read the passage, before choosing the best remaining error
interpolation strategy. This solution is absolutely unthinkable in audio terms, because in the event of errors
the aim is to privilege continuity of the musical message so that the listener doesn’t realize that the player
is correcting inaccurate data. Obviously, it’s impossible to stop the reading and to repeat a passage
several times to remove a scratch, a finger mark or anything else which could have triggered the error
correction system. In light of this, we can see how important it is to adopt a specific strategy to audio
reading and why the MICROMEGA team invested so much energy and time into developing the most
appropriate solution in terms of musical reproduction.
Digital to analog conversion: AD1853
CD10 calls upon one of the best dedicated digital-analog converters currently available. We chose the
Analog Devices AD1853 because of its unbeatable value for money. This converter with its dynamics of
110dB, its signal to noise ratio of 112dB and its THD + Noise figure of < -100dB is the ideal converter for
treating signals from the SAA7824 as accurately as possible. The power supply with constant current
source and shunt regulators ensures total immunity from external disturbances. The local decoupling
ensured by very low inductance, very low series resistance capacitors, guarantees better signal integrity
for the analog stages. The signals generated by the SAA7824 enter the AD1853 at 44.1 kHz. They are
converted internally and oversampled 8 times in a digital filter whose out of band rejection is higher than
115 dB, pushing very far back from the audio band the first images of the digital filters. That makes it
possible to have analog filters of a relatively low order while minimizing the energy transmitted out of the
band. The design of the printed circuit is critically important and the MICROMEGA team put all its know-
how into this part, which represented a challenge in more ways than one. The circuit, which was designed
using the most modern software, is optimized to take into account the extraordinary possibilities of the
selected components. Any design error can be costly, both in terms of measurements and listening
quality. The AD1853’s current outputs in differential mode enable it to preserve the intrinsic dynamics of
the signal and to reject in common mode any disturbance which could have affected the signal. Despite all
the precautions taken in terms of the layout, it may be that at certain times some external phenomena
affect the signal. In this particular case, the differential mode proves to be extremely effective. Indeed, the
principle of differential mode consists of conveying a signal in two separate branches, one of which is in
opposite phase to the other. If a disturbance affects the signal it will simultaneously affect the phase of the
two branches. When the differentiator comes into play between the two signals, this disturbance will be
totally cancelled. It is what we call in technical jargon the common mode. Therefore, we can affirm that a
differential signal saves 6 dB of dynamics and totally rejects any signal in common mode, taking into
account the differentiator’s common mode rejection factor. A subject often discussed is that of symmetrical
Analog Devices AD1853 because of its unbeatable value for money. This converter with its dynamics of
110dB, its signal to noise ratio of 112dB and its THD + Noise figure of < -100dB is the ideal converter for
treating signals from the SAA7824 as accurately as possible. The power supply with constant current
source and shunt regulators ensures total immunity from external disturbances. The local decoupling
ensured by very low inductance, very low series resistance capacitors, guarantees better signal integrity
for the analog stages. The signals generated by the SAA7824 enter the AD1853 at 44.1 kHz. They are
converted internally and oversampled 8 times in a digital filter whose out of band rejection is higher than
115 dB, pushing very far back from the audio band the first images of the digital filters. That makes it
possible to have analog filters of a relatively low order while minimizing the energy transmitted out of the
band. The design of the printed circuit is critically important and the MICROMEGA team put all its know-
how into this part, which represented a challenge in more ways than one. The circuit, which was designed
using the most modern software, is optimized to take into account the extraordinary possibilities of the
selected components. Any design error can be costly, both in terms of measurements and listening
quality. The AD1853’s current outputs in differential mode enable it to preserve the intrinsic dynamics of
the signal and to reject in common mode any disturbance which could have affected the signal. Despite all
the precautions taken in terms of the layout, it may be that at certain times some external phenomena
affect the signal. In this particular case, the differential mode proves to be extremely effective. Indeed, the
principle of differential mode consists of conveying a signal in two separate branches, one of which is in
opposite phase to the other. If a disturbance affects the signal it will simultaneously affect the phase of the
two branches. When the differentiator comes into play between the two signals, this disturbance will be
totally cancelled. It is what we call in technical jargon the common mode. Therefore, we can affirm that a
differential signal saves 6 dB of dynamics and totally rejects any signal in common mode, taking into
account the differentiator’s common mode rejection factor. A subject often discussed is that of symmetrical