Can DAC placement cause CD player skipping?

Only at the time of full moon.

DAC should always be below the CD player...in fact as a general rule audio components in a chain should always be mounted such that the earliest source is highest and the final output is lowest. (For obvious reasons, as gravity will assist in an unrestricted flow through the chain)

Skips are far more likely to be mechanical or optical problems than electronic ones. Placement of the units should not make a difference one way or the other... unless that placement affects the mechanical isolation of the transport. If, for example, your digital interconnect is under physical tension, or if the DAC is on a surface prone to vibration and the transport is on top of the DAC, then vibration could be transmitted from one unit to the other.

There are a lot of tube DACs out there, and I would not recommend stacking anything on top of such. However, the added mass of anything on top of a CDP or transport could very well make such a device less susceptible to external influences. As for stacking components on various shelves in any specific vertical order, my result would be because of cable routing and not because of gravity.

>> in fact as a general rule audio components in a chain should always be mounted such that the earliest source is highest and the final output is lowest. (For obvious reasons, as gravity will assist in an unrestricted flow through the chain) <<

I just *know* you can't be serious, right? If you are serious, Lord help you...
-RW-