I use a MT-2 to boost my amps sometimes, I keep the drive all the way off, level cranked, eq section all at noon... which keeps it as neutral as possible, just tightens things up and gives the amp a gain kick. Gives you a really heavy Crowbar type tone in B tuning.
I find if you start messing with the EQ section it just leaves you with a thin sound. Maybe the modded metal zone's have a more usable EQ on it?? They seem to sound a little thicker as a stand alone distortion when modded (the Keeley one)... But I wonder if modding the mt-2 would kill its sound as a boost?? Cause it's got nearly the perfect natural EQ for boosting when it's set at noon flat, has a nice edge/attack to it that a sd-1 or ts9 doesn't have.
