He could move the existing preamp to within the 10’ of the amps.We won't know until Ron gets a new preamp (or uses his current preamp), places it within 3 meters of the amplifiers and plugs it directly into the amps, bypassing any other additional circuitry .
We would know more then, than we would with also switching the preamp.
The in second scenario the preamp and the cable are both swapped out.
It is often easier to just swap out one thing at a time, to get a better understanding of what’s what.