A couple of days ago, I had a student in a combo who was thinking that the amp he was playing was blown because when he really dug into the string, the amp would make a farting noise. On a hunch, I took his cable and reversed it so that the end that had been in his FC pickup jack (which was a 90 degree end) into the input of the amp (a Contra), and everything worked fine. ***? The only thing I can figure is that the diameter of the 1/4" plug was slightly too small, making the connection go in and out when the vibration in the afterlength rattled the jack. Has anybody experienced this phenomenon, or know of other cable ****age to be on the lookout for? If I hadn't gotten lucky and guessed right, that amp would have been out of commission for a while for no reason.