Articnoise
Headphoneus Supremus
Part 2. The question is what is DI20 clocking and if the DI20 really is operating in Asynchronous?Thanks. I'm still a little confused about when the DI-20 clocks are/are not used. I was under the impression that the Di-20 clocks are used when going out over I2S. It seems this is not the case. So just for my knowledge, when in fact would the DI-20 clocks come into play?
DI20 clocks the incoming USB signal and converts the USB signal to one of the following: SPDIF or I2S. In order to convert the signal, it needs to be clocked, i.e. re-clocked. Yes, it must be re-clocked because USB, I2S and SPDIF are completely different types of digital interfaces that do not speak the same "language".
Because DI20 only has USB on the input and no USB output means that DI20 cannot be controlled by Asynchronous USB from the DAC. No USB cable between DAC and DI20.
That means that when you use SPDIF out to your DAC, it is DI20 that dictates the timing for the packets to be sent to the DAC. With I2S, it depends on the DDC because the I2S interface/protocol can be made to operate both as asynchronous and synchronous.