So I've searched and read several threads on here but none seem to hit the nail on the head. I'm hoping someone can help. Here's my situation: I bought a used '01 Streamer Stage II 5-string. Sounds beautiful in passive mode, actually I want to say it sounds a bit cleaner or brighter in passive mode but too bright for my taste. In active mode, with the low/mid/high in the middle, the sound to me seems a bit "darker" but nevertheless very nice. I am currently using a Little Mark II amp and a 4x10 MarkBass cab. I didn't notice any issues when I bought the bass and I've used it for a few rehearsals at various volumes. Everything seemed okay. At the last practice however, the guitarist used my bass and was messing with the knobs. When he handed it back he left the bass boost all the way up. When I started playing I heard some distortion on the 5th string and on some of the lower notes on the 4th string. I had never heard this distortion before, perhaps because I never move the knobs and play with everything flat. For troubleshooting purposes, I removed all pedals and plugged straight into the amp. I don't think the amp itself is clipping, at least the clip light doesn't come on. Regardless, I've tried turning down the gain to no avail. I tried a brand new 9v battery and that didn't seem to make a difference. None of the wiring seems out of place, but then again I probably wouldn't be able to spot a problem. I read the Warwick manual and the pickup/string height all appear to be okay. I don't think contact cleaner would solve the problem because it's not the kind of scratchy sound the knobs make as you turn them when they are dirty. It simply sounds like an overdrive kind of distortion, and only in active mode when the bass knob is turned up more than about a quarter past the half way notch. The harder I hit the strings, the more distortion I get. One other thing I've noticed regarding the treble/mid/bass tone control knobs in active mode: when I adjust the treble and bass, I can clearly hear the difference it is making in the tone. The highs go from bright to dull, the lows go from fat and boomy to flat, but I can't really say the same for the mid knob. I can sorta tell something is happening, but when I play I don't feel that it's making an impact. With the mid all the way up, I can't find any notes that jump out more or vice versa. Don't know if this might be an issue too. (Could this explain why my tone sounds a tad "darker" in active mode versus passive? I've never owned a streamer so I don't have anything to compare to). I should add that I noticed some wear on the pickups, almost as if from the strings rubbing up against them. When asked the guy said he played "hard". Also, this is happening with the pickup balance knob in the middle. Anyways, would anyone have an idea as to what the issue might be? I hope I provided enough clues. In general, I'm very happy with this bass. It's very clean and seems to have been taken care of very well. The tone is all around amazing and clean, a world of a difference from the active jazz bass I was using before. I probably would have never noticed anything had my guitarist not left the bass boost all the way up. I could probably live with it the way it is now, but it's killing me knowing that something might be wrong. Any help would be greatly appreciated!