I am just piping in because the PF50T grind when pushed is as distorted as I would ever need to hear a bass signal distort... Tube distortion that is....I have the Ampeg DI SCR and I can dial that grind in very softly...but all I have read on TB many people dont even consider that distorted enough? Maybe that would be the "mellower grind" you are after....it seems there is a very, very fine line between pleasant and unpleasant "tube" or "tube-like" distortion...all is the ear of the beholder. I like the v4b grind I can get as well as the grind off of the SVT-CL...so I am crazy biased on Ampeg tube sound..and the tube breakup of those amps is what many people here consider to be a standard of some sorts. Just my 2 cents, hope you find a cool pedal or combo that gives you the sound in your head you are after.