Before I got OTB500 I got a big scared about the DI 'issue' so, I got a -20db attenuator off've eBay for a fiver - never used it!
I did swop out the JJ's it came with (which was a suprise!) for some old Sovteks to calm it down a bit. 10 screws and a few twists of the valve covers, done in 5 mins.
It is an amazing bit of kit, although the rest of the band call it the Toaster! :-/