I bought a used Gibson EB5, 2017 model, through the mail from a nationwide seller. I listened to about a dozen audio clips on youtube and the Gibson website. On the videos the bass had significant tonal variations with the tone knob, which is a treble cut, switching pickups, and switching the pickups to the "tapped" position. The EB5 I got doesn't seem to have these tonal variations. When I turn down the tone knob it just doesn't seem to cut the treble that much. When I switch pickups it also doesn't change that much, and same thing with the pickup coil taps. By comparison my passive Fender Jazz has a lot of change when I adjust the tone knob or turn down one of the pickups. I suspect the Gibson had an electronic mod by the previous owner because there are a couple of other minor mods to the bass. So, does anybody know a good way to see if the electronics were modified? I'm attaching a picture of the electronics cavity. The pickups look totally stock. Maybe other EB5 or EB4 owners can compare it to their own. A Gibson rep on the phone said all three pots are 500 k. But I do like very much the deep growly and powerful sound of the bass. I also read at least one posting on this website from a guy who said his Gibson has the same situation. Very little tonal variation, but still has one great sound. I'm running through an Orange Crush Bass 50 Watt 1X12 amp. Thank you.