I'm afraid this is impossible to answer, but it's bugging me so I have to try. I'm just getting back into playing after years of inactivity, but I was never very knowledgeable or good with gear. For weeks, if not the months I've been playing I've felt there was something "off" or not quite right with my bass tone. I have trouble describing it. Closest I can come is that it's not quite as clean or as smooth as it should be. My guitarist, drummer, and my son don't hear it but I do. I thought it was my bass, maybe pre amp, tried changing the battery, sounded the same. Tried another bass that is a dead silent passive P bass. Same thing. A possible clue, or possible "red herring" - One time recently while jamming I completely lost sound suddenly. I couldn't find the reason. Randomly flipped switches, unplugged the bass going to try another battery knowing it was basically new, but it didn't make sense so plugged in for one more try, and sound was back. I told myself I must have stepped on the cord and been unplugged, but I was using a 90 degree end cable tucked behind my strap and into a side mount input jack. I really can't see how I came unplugged. It was super hot in the room that night and wondered if I overheated and it had time to cool down? Another possible clue / possible read herring - I blew out speakers on my cab. I posted up a thread about that and chocked it up to playing too loud for a 2x10 - but I think I overstated how loud we were and I swear I've played that cab that loud before without incident. I wasn't pushing much low EQ really. A played a different cab and hoped it had all been the speakers for the past several weeks. Basically a mint condition brand new 1x15 and I didn't push it. Still heard that tiny bit "off" and not perfectly clean sound. Very minor low mid / high mid EQ bump. Tried EQ flat, still heard that weird quality to my tone. Sounds almost like clipping, but no clip light and per gain is low. My son said it's an "only you can hear that thing". It's minor not an obvious thing, but I swear there is something. The amp is a Trace Elliott AH250 and I believe it's about 30 years old. I've owned it nearly ten years. It lived in my basement the last several years and was played regularly by my sons band. When I moved recently I realized everything in that basement was much dirtier than I was really comfortable with, so it had been exposed to dust and dirt and moisture, possible mold and mildew if not directly. It stayed safely atop speaker cabs and didn't get wet the six times the basement flooded. I just hear this tiny bit of "not right" in my tone. I'm intimidated to take the head apart to clean inside "just because". I can't even prove there's anything wrong with my sound. Is there some sort of dummies guide to checking amplifier function. Am I losing my mind? Any advise?