+1 on the Carvin BX1200. It was on sale for 500.00 just a couple of weeks ago, which is a sick price for an amp with it's capabilities and construction. My previous amp was the GK 700rbII and it was a great amp, just not in the same class as this bad boy.
Specs; 2 x 275w RMS @ 8 ohms each, 2 x 400w RMS @ 4 ohms each, 1200w RMS bridged @ 4 ohms.
The DRIVE control on the Carvin does what I wished the GK's boost control could do, which is woolly up the sound to Trace-like warmth.
The X-OVER (or bi-amping) abilities of the Carvin are very unique and useful also. Great for mis-matched cabs, like a 15" cab and a 210 because the CROSSOVER FREQ knob acts like an active crossover unit on a PA system (with subs).
With it's footswitchable graphic EQ and DRIVE, you can tune up two different basses (like an active and a passive) and with one stomp, you can switch the basses without turning any knobs. It's got everything. Originally I thought it was too complicated but now I realize it's just a very well designed unit because it gives you all the choices.
Honestly I believe this head, when paired with the right cabs, is right there with GK's 2001rbII.