Ok, let me explain, my band does not have a bass player, I play guitar tuned to drop B through a bass rig and a guitar rig. The guitar providing the mid and high frequencies, and the bass obviously providing all the low end. I play a Tubescreamer through the guitar rig, and a Fulltone OCD through the bass rig. We play very fast, sometimes slow, very heavy, very loud, grinding and spastic hardcore (not XXX hardcore) Think a blend of Botch and Black Cobra. I know this all may sound like blasphemy to the bass community, but it is what it is, and i feel like this might be the only place that can help me.. My setup is as follows.. My guitar rig is a 77 Marshall 100w JMP Super Lead, through an orange 4x12 and 2x12. My bass cabinet is a custom built 4x15. I originally was using a JCM 800 MKII Super Bass, but it just couldnt deliver the low end at the volumes needed to keep up with the JMP, or my loud ass drummer. So I sold it, and for the time being, until I get a new head, my friend is letting me use his Ampeg B4R. I will say, that the B4R sounds amazing, and does get loud enough, my only problem is that when i dial in the volume to where it needs to be, it doesnt stop peaking. I feel like i need something with some more headroom. So here is my question.. Ive been interested in a few different amps, and I'd just like to know what you all think. My options are the Ampeg SVTII Pro (or non pro?) the SVT4 Pro, the Mesa Boogie 400 ((or 400+?)(i feel like the 400+ may have the more power needed for my application)) or I was also looking at the Fender Bassman 300 Pro/Sunn 300t, but i've heard about problems with those. I AM sort of concerned though, that an all tube head might sound too farty with guitar. My only experience with an all tube bass head was the marshall super bass, which didnt work for me. but my experience with the solid state (the B4R) has been good, as far as tone.. What do y'all think?