I would consider a tube preamp for the SDS. I have the CDA amp and my tube preamp smooths out the brightness and the sound is stunning. Here is an AR LS-2b at a great price, it comes with a remote-

Audio Research LS 2B mk 11 R | Tube | Fairview, North Carolina 28730 | AudiogoN - The High-end Audio Community

I have good friend that runs this with a pair of Nuforce Model 9se monoblocks and PSB Synchrony's.

This Van Alstine T-8+ with remote is excellent as well, it is the preamp that I should have bought instead of the Hybrid Ultra preamp.

Van Alstine Transcendence 8+ With Phono and Remote | Tube | Sugar Land, Texas 77479 | AudiogoN - The High-end Audio Community