Better cables will not always sound better on source to preamp? IME sometimes the better cables perform better from preamp to amp. Experiment always is the key and matching.
Where to put best interconnects
Getting a new tube pre-amp into tube mono blocks with one CDP as front end. Will have one very good, new set of XLRs to use and one good but much older set, each at 1.5M. Where to place the better set?