there is a lot of talk about clocking and re-clocking. in a normal transport/computer to dac connection, there is no clocking or re-clocking. except if you own certain esoteric or dcs components. to do clocking, these devices would have to work on a peer to peer basis and if the dac receives invalid data, it forces the source to retransmit or reread the data (esoteric calls that flow control). esoteric and others sell external clocks which are very expensive and they only work on certain sources.
here is a quote from Thorsten Loesch:
"In reality, it is relatively easy (i.e. low cost) to make a clock crystal with high precision (<0.5ppm). However, making a clock crystal with low phase noise (jitter) is much more difficult (i.e. expensive). Perhaps that's why the aftermarket so-called 'super-clocks' often quote the former and omit this latter and more relevant specification. Just as importantly, the use of more than one clock (even a 'super clock') if it is not synchronized to generate a master clock signal, will mean that the issue of all clocks being out-of-sync with one another has still not been addressed. Again, this leaves the other major source of jitter unresolved."
here is a quote from Thorsten Loesch:
"In reality, it is relatively easy (i.e. low cost) to make a clock crystal with high precision (<0.5ppm). However, making a clock crystal with low phase noise (jitter) is much more difficult (i.e. expensive). Perhaps that's why the aftermarket so-called 'super-clocks' often quote the former and omit this latter and more relevant specification. Just as importantly, the use of more than one clock (even a 'super clock') if it is not synchronized to generate a master clock signal, will mean that the issue of all clocks being out-of-sync with one another has still not been addressed. Again, this leaves the other major source of jitter unresolved."