While cable length can influence the problem, the real culprit is impedance mismatching.
I don't get it. I can run my guitar through 7 pedals and 6-8m of cable and get virtually no loss (when bypassed) of treble, but when I run my guitar through 2 factors, both relay bypassed and a really short cable (same type as previously, George L's) I suffer loss of treble. If I use the same cables and no factors I get no treble loss so its not the cables.
I do understand how impedance mismatching can influence how the cable capacitance leads to treble loss, but how is the impedance being affected when the factors are bypassed? through the relay?.
Let me spell it out again. I ran a switched loop, to both my factors in series with very short George L patch cables. I can switch the loop in and out so I am A/B'ing the tone. I deliberately hide the LED on the loop box so I'm not influencing what I'm hearing. I can tell when the bypassed factors are in circuit., its audible. Now if I replace the factors and patch cables in the loop with a 5m George L's cable, considerably longer than those patch cables, I cannot tell which is which when A/B'ing. So if the cables are not creating the conditions of which you speak, the Factors are, but how?