I know this an ancient thread, but I can tell you that the SD1200 is my favorite non all tube amp. It's head room is endless. So much so that i use high pass filter( usually set at 32hz) with it. It has so much slam that it makes even high wattage speakers go into thermal compression. I don't know of a louder amp. It's tone is very much like the venerable Markbass F1/500.I don't know, but there was one gig where the rented SVT they had for me took a tube dump a minute into soundcheck, and I had to do the gig with the SD1200 they brought as backup, and it was pretty darn decent.