Distortion on lowest notes

[Sebek-Ra89]

I'm not sure where to put this so if this is the wrong place please move it mods. With that out of the way I went to GC to try out new amps with my new Thumb B.O since I traded my old head for it. I tried it out of an SVT4-Pro and it sounded fine but since thats what I traded for it I am looking for something new so I try out a Mesa. While trying the I notice that the low D to the low F# on the E string were distorting; I thought it might be the amp so I put it on passive mode, same thing happened. Then I tried the rest of the Mesa's and the GK's and the Mark Basses and then tried them all again with a different cable; all had the same issue. Then I bought a new battery and went home and before putting the new battery in I tried the bass on a little Peavy combo and the problem was not there. So the question I am asking is if anyone knows what is going on and or how to fix the problem?

[staindbass]

i think the input level was just overloading the inputs? i wish i had more to say... odd problem. does the bass have a level control in the pickup control cavity you could adjust?

[SGD Lutherie]

Try lowering the pickup under the E string.