@debjit_g I would like to clarify and reword my last post.
When I wrote that post, I had in mind what melm said: "I believe what I am reading about here IIUC is not a comparison of the USB input with the I2S input. It seem to me rather a comparison of 2 USB inputs, one using the internals of the Musetec USB system and the other using the separate LKS system, both feeding I2S into the internals of the DAC."
Viewing the comparison in that way is interesting and it made me think what in my experience would explain why the L.K.S Audio USB-100 DDC could sound better than the Amanero board built inside the 005.
Some potential advantages I see are:
- As viewed from the DAC chip, the electrical noise from the DDC will be less than the electrical noise from the built-in Amanero board because the DDC is farther away from the DAC chip.
- The DDC has its own power supply and this has a number of benefits including...
- The DAC's power supply is freed from the task of powering the USB to I2S function, which should allow it to better supply power to other parts of the DAC.
- The electrical noise generated from the DDC should have a smaller impact to the DAC's power supply compared to the Amanero board because the Amanero board is connected to the DAC's power supply and the DDC is not.
- The DDC has a singular task to convert one digital signal to another and if its fed by a very good power supply, it alone will take full advantage of that power supply. Usually, the better the power supply, the better the performance of the DDC. In this way, the performance of the DDC is scalable and its theoretical performance ceiling may be higher than a static built-in solution like the 005's Amanero board.
- The addition of a DDC means adding a reclocker and if the DDC has a well built clock, this can have benefits downstream to the DAC. Signal integrity may be better.
I can list the drawbacks of the DDC as well but in my experience, choosing the right Digital-In to Digital-Out type devices can create wonderful sonic improvements.
For these types of devices I look for a great clock usually of the OCXO variety and a special built power supply that is built inside the device itself to eliminate external DC cables. It's a winning combination and the sonic improvements have not been subtle for me.