Glad you love them. That is the main point, afterall. Also I meant zip cord was 3 to 4 times Worse than my MITs. I got it swapped around. Maybe that is why Bob contributed nothing in his post.
In all wires running near each other, capacitance can be a problem especially when electromagnetically coupled with the wires' inductance - something that will invariably occur in any pair. The capacitance is between the wires and inductance is in series. This coupling will cause slight signal phase variations in the current due to flux variations due to frequency changes, known as ringing, so there will effectively be ghost frequencies "contaminating" the sound (visible on an oscope). Whether these are audible or not is the question since they generally will be only at very high frequencies, but regardless, it is always good to have runs of wires separated by at least a couple inches where possible to eliminate capacitance. However, with increasing length, the capacitace decreases and inductance increases so there is an optimal length acheivable (not too long and not too short).
All of this is true UNLESS you have well shielded cables - the main design objective of all good audio cables. Best way to not have contamination is to not let it "in" in the first place - something zip cord cannot do hardly. This is the condensed version of wire dynamics and illustrates why copper zip-cord wire is not much different than copper Valhalla wire. The cost difference is mainly in the shielding and somewhat wire quality with the main objective to lower inductance (and resistance although that is more of a efficiency solution than audio-noise solution) and to shield from the flux of neighboring cables. MIT attempts to correct some of these phase effects, that nevertheless happen - nothing is perfect remember!, with their passive element boxes in the cables but I am not convinced that they do a whole lot since excellent correction of these problems is only really acheivable with ACTIVE elements (as used in balanced amps and preamps with balanced connections) but then you have a catch-22 situation because active elements add noise themselves.
I left out many details but it does not matter since your ears can tell you everything you need to know. I said all this to objectively support my argument above (not to mention the well-known Law of Diminishing Returns...). Just listen and see what you budget will allow. For MIT, I find audio advisor to have good prices on new stuff but Ebay is the best in general if you ask me.
Arthur
