I voted " other ". Although the preamp is Class A, the two power amps are class D in the Carvin BX1500. I have tried the following : GB Shuttle 6.0 and 9.0, ShuttleMax 12.0, MB LMII , F1, and TA501. The BX1500 is the best bang for the buck bass amp I have ever owned. It has more options like compressor, 2 ohm capable, crossover for bi amping, two EQ choices that can be used at the same time, or singly, etc. It is basically a dual power amp with a preamp around 10 pounds. It has the best graphic eq I have ever used, and into a 4 ohm load, I'm getting 1500 watts. All this for under $600. My only gripe about it is that it has to be rack mounted, adding weight and bulkiness. The case Carvin offers does not have a front cover for it so I don't see the point and its rather heavy. The BX1500 is light enough to fit in a large laptop bag which would add little weight, but sadly, Carvin does not offer the amp in a non rack model. I have all the power I will ever need, and more options to do whatever I feel like, with any type of cab(s) I'll ever try. A no brainer for me.