I'd start with DAC to Preamp. Then move. While it is logical that the furthest up the chain will have the greatest impact, components are different and react differently.... so, it still might make a bigger difference elsewhere. But I'd start with the DAC.
XLR cable placement
I just bought a new (used) XLR that may possibly be my best cable. Right now I have the same brand XLR's going from my DAC to my preamp as well as going from the preamp to the power amp. My power amp only accepts XLR's.
Would I be better to place my new best XLR's between the DAC to the preamp, or the preamp to the power amp?
Thanks in advance