I'd second that. I didn't notice any particular lessening of the treble upon switching from the modi uber to the multibit. If you wanted to upgrade to a tube amp, and then roll tubes, there are definitely ones out there that have lower treble profiles. However, that is a whole heck of a lot of money to fix something that you can do for free with a dash of EQ. Also, I'd suspect finding matched quads of tubes for the Valhalla could be quite a pain. Its hard enough finding well priced and matched pairs. Best of luck!