Hello again, I am here with another question. When I turn on my amp and start playing, I have a pretty pounchy and defined sound. I turn on the amp with both bass knobs (P bass) on, and Gain and volume levers off on the amp (Mag300). I turn them up as much as I need, play, and after some minutes the sound literally starts losing fullness and it gets brighter, at the point of being half as bass in tone as before. I have first noticed that in a small combo, and thought it was its fault. Paying more attention I realised my amp too does that, so it is no amp problem, nor cable. I will take my bass to repair anyway but I won't manage to do that for a while, so I ask you, what in the world could cause this sound change? I hope it's notvsomething obvious I nooby didn't know. The bass has F Original 1962 pickups, aftermarket cheap jack and the rest is standard mexican wiring. Thank you!