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? The pickups look totally stock. I'm attaching a picture of the electronics cavity. I'm not sure if the picture says much. 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 growlly and powerful sound of the bass. I also read at least one posting on this website from a guy who said his Gibson, not an EB5 or EB4, has the same situation. Very little tonal variation, but still has one great sound. Maybe this is just a Gibson characteristic and the youtube videos were very high fidelity. I'm running through an Orange Crush Bass 50 Watt 1X12 amp. Thank you.