Cable runs and effect on tone

[daz]

I want to make a volume boost box to put in a effects loop. I hace done this for years when i was gigging but i had a small rack on top of my amp to control a pedal and for a rack effects processor etc. So i had short patch cables going from the loop send to a relay that bypassed a pot used as a attenuator and back to the amp's return. This way I could set the pot for a tiny bit of attenuation which would be my main volume level, and when i bypassed it by controlling the relay from a footswitch i'd get a bit of a volume boost for those moments it was needed.

So now i'm using a modeling amp and i do occasionally play with friends or a rare gig. No rack like before to use as a housing for a relay and all that like before. So i want to use a box with a switch and pot and run cable to and from the return and send on the amp. So unlike before instead of short patch cables i will need to run maybe 20' of cable in total. I have 2 questions about this. 1-being at line level, will this degrade tone to any notable degree? and 2-if i use 2 conductor stereo cable so i can use just one cord, will the 2 conductors side by side for about 10' cause any issues ? And to answer the inevitable question i foresee some asking, i would use a Y cord at the amp to plug the stereo cable into.

[The Dude]

I do almost this very thing with one of my rigs running a multiple effects pedal out of the effects send to the floor and back to return. Never had a problem. You are much less likely to notice a noise problem on a line level signal by virtue of the fact that it is a hotter signal. Noise would be much more noticeable on a guitar level signal. I used microphone cable using a common ground, one wire for send and one for return. I just split out the ends to two connectors (done nicely with shrink wrap) to negate the need for Y cords. The cable is about 25' with no noticeable loss of gain and no extra noise.

[daz]

I do almost this very thing with one of my rigs running a multiple effects pedal out of the effects send to the floor and back to return. Never had a problem. You are much less likely to notice a noise problem on a line level signal by virtue of the fact that it is a hotter signal. Noise would be much more noticeable on a guitar level signal. I used microphone cable using a common ground, one wire for send and one for return. I just split out the ends to two connectors (done nicely with shrink wrap) to negate the need for Y cords. The cable is about 25' with no noticeable loss of gain and no extra noise.

Great. Thats what i'll do then. Thanks. I've always feared long cable runs because it's those subtle things that you don't notice right away that sometimes will screw with your tone and by the time you realize it you've wasted a lot of playing time with tone thats not making you happy.