Aaron, I had tried several preamps with my Kismet mono amps to do A B C D ... comparison. A list consist of Cary SLP-98, Rogue 99 Magnum, Triode Corp TRX-3, Audible Illusions 3A, Fisher, Scott, Harman kardon Citation I, & a few others that I don't remember. No need to go into further descriptions of each sound as everyone has different ears but for now I have 2 Candelas + a Tempest. The Candela is the best for me at this time. I would be willing to try Backert Labs if anyone can bring it over my place for comparison. I hope in a few weeks I would be able to try them with the Symphonic Line RG3 MK4 with the all out separate Turbo Power Supply.