Amp suggestions for Theta/Adcom/Snell

I recently replaced an older Bryston amp (4b nrb series) with a Theta Dreadnaught-2. Theta Carmen/IIIa dac, Adcom GFP-750 preamp, Snell C/V mains, Rel storm3 sub. Tara Labs and Synergistic Research cables. The dreadnaught has a sweeter sound that I definitely prefer in the highs and mids. However, the bass is kind of weak compared to the Bryston, and the Bryston also localised the instruments much better. Any suggestions for a multi-channel amp that will give me the good characteristics I mentioned of both? I know I need to replace that preamp, but I'd like to get the amp right first. I need 5 channels of amplification at about 2500 used. Thanks in advance. -Dave