So...I really need some help here. I posted the other day that I thought my battery in my Spector Euro 4lx was going down way too quickly, as I play the bass plugged in maybe 8 hours per week and was having to change the battery every 1-2 weeks to keep the tone sounding good. I had also had some issues in the past with the jack going in and out. After several TB'ers advise that I get a new input jack, I took the bass to Guitar Center yesterday and got a new jack put in. The tech, who I happen to know is very competent, put in the new jack, cleaned some pots, etc, no issues. I put a fresh battery in while he had it open (Just to clarify I'm using good duracell batteries), he plugged it in and it worked fine and I went to band practice. Plugged it in, played for maybe 2 minutes and then the volume of the bass just dropped off and it started making this crazy crackling noise when I would move the bass and especially the jack around. I tried it with two different cables and it did the same thing, and I also tried another bass just to make sure it wasn't my rig. It wasn't. I took the bass back to GC and told the tech what happened and he seemed pretty surprised as he said that normally an input jack would be either bad or good, not inbetween. Of course, he plugs the bass in and it works just fine and went out just a bit. He checked and said all the connections looked good, but for giggles re soldered a few wires, as well as a ground. I pulled up the Spector wiring diagram for the 2006 euro, which I think mine is, and when he looked he noticed a discrepancy with the ground cable and re soldered that. Took the bass and played it for a sec and it worked. Got back to practice, played for about 25 minutes and it starts up again, volume dropping, crazy hissing sound etc. We had a show in a few hours, so desparate to see if I could fix it, I took the back cover off and poked around at the wires while it was plugged in to see if I could isolate the problem. I took the battery out of its home in the velcro sleeve and when I moved it around the hissing got worse. So I grabbed an old, already used 9 volt and swapped them out. My tone wasn't nearly as strong as it's been, but with the used batttery the hissing stopped and the bass was playable. I then put a DIFFERENT new battery in, and the hissing went crazy again. So, I put the older battery back in, headed to the show and tried to play the bass for a few songs but noticed my volume dropping off, so I finally switched from my $2000 Spector to a $170 Squire I picked up a few weeks ago. Bummer. So, does anyone have any semblance of a clue as to what could be going on? I'm taking it back up there at 5, but I'd like to have some suggestions. Sorry for the novel.