This isn't a mod, but I found a good way to eliminate a lot of the fizz from my Roadster. Turn up the master, turn down the gain is a good one. Also, I turn my treble down to around 9:30 (on a clock) and push my mids up to around 2. Keeping your treble setting down could make a big difference- it did for me. Even with my treble at 9:30 my guitar's tone knob is still at 6. For my situation, I'm just having to learn how to make tasteful use of the Recto's MASSIVE amount of high end and gain- maybe you can do some EQ tweaking without having to drop hundreds of bucks for a Voodoo mod.