To DDC or not to DDC. That is the question.

I use 2 DDCs in my system. Both my streamer and DAC have galvanically isolated USB, yet the DDCs are doing god’s work. Research some good DDCs and see what pops up that interests you. Then weigh against the DAC upgrade. Either route will probably get you to about the same place.   

I use Galvanic isolation and DDC  each one  paired with Buffer/filters and each one powered by LPS.

I used my ears to decide to upgrade or  not my optimization process ...

Everything cost peanuts (from China) 

 Each time was improvement ....

@jacupmakeup 

I also use 2 DDC's between my streamer and DAC as it is better than direct USB.  I think the clock in the DDC does not have to be better than the DAC's for the DDC to provide benefit.  Just avoiding USB noise can have enough benefits that an inferior clock can still benefit the DAC's performance.

@rikkipuu yep I believe you are correct