From the dCS Debussy user manual I have read that:
“So far, when using the PCM inputs, the system has been set up to lock to the clock generated by the source. This is the simplest arrangement, but it does not give the best sonic performance due to clock jitter. If the source equipment can be locked to word clock or the USB interface is selected, the performance can be improved further by adding a Paganini Clock to the system as shown in the example below”
My question is why the external clock must also be connected to Debussy? If Debussy has been set up to lock to the clock generated by the source and we connect the external clock to the source. What does Debussy use the external clock signal for when it is connected to a source with the same external clock?
As the User Guide states, using an external Master Clock connected to the DAC and source reduces jitter in the system. If you have the option of using the external Master Clock, it will reduce jitter and provide you with a higher level of sound quality. The key is that (with the exception of asynchronous sources like USB) the clock must be connected to the source as well as the DAC.
If the Debussy sees a valid Word Clock Input signal from a connected Master Clock, it will use that instead of the embedded clock information in the audio signal. The Word Clock indicator on the front of the Debussy will let you know if this is happening:
If it is illuminated, the Debussy has detected and locked to a Word Clock signal.
If it is not illuminated, it cannot detect a valid Word Clock signal. In this case, it will lock to the clock information in the audio stream instead.
If it is flashing, the Debussy has detected the signal but cannot recognise it or the Word Clock signal is at the wrong frequency. In this case, it will lock to the clock information in the audio stream instead.
As above, it uses the External Clock. Having both the source and DAC locked to the same external clock reduces jitter, reduces audio dropouts, and generally makes things better, so by default the Debussy will use this if it sees a valid Word Clock signal.
I have been reading the dCS Forum for a long time. Untill now I have found all the information what I needed without asking
James, thank you so much for a clear answer. That is what I thought, but after reading the instructions a small question mark appeared in my head.
Thank you.
