Hi JohnnyR,
As I mentioned earlier in the thread the line-level input impedance of the SVS SB-2000 is 47K, which is much higher than the line-level input impedance of many and probably most other powered subs. In combination with the 22K input impedance of the OP's amps that will result in a 15K load being presented to the preamp, significantly higher than the 10K minimum that is recommended by Conrad Johnson for the particular preamp.
Regards,
-- Al