I finally got to really try out my newly purchased Mesa Boogie Rig ! It is a M/B 400 (not 400+), a brand new M/B 4x10D diesel, and a slightly used M/B 1x15 diesel (won on ebay). Holy cow ! This thing is a monster. I had a smile from ear to ear for an hour till my cheeks hurt. I can't imagine having the 400+ head with almost twice the wattage. And what a sound, It's also my first tube amp. So far reading and posting on TB has turned me on to: Tube amps, 4x10 cabs, and fretless basses. I never had an interest in these things before, and i've been playing for 20 years. Thanks to everyone at TB !