Measure the resistance of the cable. Take your cable resistance and cable capacitance and plug it in to the calculator here: http://www.learningaboutelectronics.com/Articles/Low-pass-filter-calculator.php There's your frequency cut-off (roughly; real-world electronics with all its gallimaufry rarely matches up with exact math) I have two 10' cables; they measure 40Ω/420pF and 20Ω/700pF. I calculate 9 and 11 MHz, respectively. Absolutely nothing to worry about at all. This doesn't take into account low-pass effects of amp/pedal impedance, but suffice to say as long as its 500kΩ and up, it will have a minimal effect. [EDIT] @TeleTucson, I just saw your post that was much more concise than mine. I was on Electronics 101 autopilot and probably posted frivolously. See below.