4.5 Advanced clocking
When connected to the CH C1 DAC, different clocking scheme can be used, depending on the D1 and C1 options. Some are simply
not working at all (no sound will come out of your DAC, e.g. because at least one unit doesn't lock its internal clock to the
configured clock source), some others will work for some time before muting (e.g. in case more than one unit is configured to lock
to its own internal clock), some others will work fine but won't be optimal depending on your hardware (e.g. using D1 as clock
source and C1 as clock slave when equipped with SYNC_IO boards), while others will bring you the joy associated to pure musical
emotion.
Recommended use cases for various configurations are detailed in the following paragraphs. Even though this chapter is quite
technical, we kindly ask you to take the time to read it in order to get the best sound out of your CH system.
4.5.1 General clocking considerations
In any configuration, there must always be no more and no less than one clock master. In CH product range, the clock master is the
unit clocked on its own internal clock (parameter clock source is INTERNAL). It can be a CH audio product (D1, C1), or an external
clock generator (T1).
If more than one clock master is used, the system is no more synchronized (at some point a unit will display “CLOCKING ERR.”). If
there isn't any clock master, each unit gets synchronization from a unit that is clock slave itself. This kind of system is not stable
clockwise. If the configured clock source (e.g. SYNCHRO BNC 75 Ohm) is not connected or has no synchronization signal, the C1 can
not lock (open padlock symbol displayed) and mutes its output.
4.5.2 Without SYNC_IO board
When a D1 with no SYNC_IO board is used together with a CH C1 DAC (or other DAC), both audio data and clocking goes from the
source to the DAC. More precisely, clocking is sent with the audio stream. It is either carried on dedicated lines in the CH Link (while
audio data is carries on other lines in the same cable) or embedded in S/PDIF's bi-phase modulated signal. Schematic below shows
optimal way to connect such system:
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