It's possible you might get some increase in volume if your bass has a low output, but I think you're most likely to end up driving the preamp into distortion rather than getting any real increase in volume.
Did HW say it was just the fuses that made it a dud ? If so then I think I'd be in there myself...depends how confident you are with a soldering iron. Removing the board would be most of the job by the looks of things.
No chance of the refund once you do tinker tho...