I took my friend (and bandmate's) Hofner "Contemporary Series" Club Bass in for a setup a few days ago. I just picked it up today - he had LaBella flats put on it - and the strings feel and sound great, but it's buzzing like crazy. I checked the neck and it has a very slight backbow and the truss rod needs adjusting. After being slightly annoyed that it even needs a truss rod adjustment after a professional setup, I decided to just adjust it myself. I've done my own setups and I know what I'm doing, but none of my allen wrenches would fit. I checked the truss opening with a flashlight and noticed that the truss rod adjustment opening is round, not hex-shaped like an allen key should be. I wondered if someone just stripped the allen slot, but it looks way too round for that to be true. Usually if a screw or hex-shaped hole is stripped, you can still see the ridges that used to be there, they're just more rounded. This looks totally round and sort of conical as it goes down. Do I need a special tool to adjust this truss rod? That would explain why my guy didn't adjust it, although it's still a bit annoying that he didn't let me know. I checked my friend's case and didn't find anything, but I did find a website selling a "Hofner Truss Rod Adjustment Wrench" made for their German made line of basses; it specifically said "not for use with Contemporary Series basses." Anyone have any idea here?