I recently bit the bullet and upgraded my bass rig from a Peavey TNT 115 to an SWR Bass 350 head and an SWR Goliath 3 4x10 cab. WOW!! I love playing bass again! Talk about awesome tone...My Jazz Bass GROWLS through this little unit. Now for my question. The owners manual says its putting 220 watts into this 8 ohm cab. The head is rated at 350 watts into 4 ohms. What will it put out if I add a Son of Bertha 1x15 cab?? I really want to add a 1x15 for the added bottom, but I'm not sure what kind of power this head will put out with this combination of cabinets. Can anyone help me out?? Thanks in advance.