The preamp is the heart of my system. I use a DAC with perfect measurements and class D amplifiers, on a multi-amped fully horn loaded system.
The amps by themselves sound a bit sterile, and the DAC while very good for the money doesn't add much "flesh" to the bones. The active crossover can be considered as transparent as can be.
My (vintage) preamp, on the other hand, is wonderful. It's a rather unknown model (Korn&Macway SP100) built like a high end device, and I recapped it using NOS Roederstein Gold caps in the PSU and Elna SilmicII everywhere else. It is majorly responsible for the musicality of the system. I've tried without preamp, I've tried other preamps, I keep coming back to it for its precise yet lush presentation. It's like it's holding everything together. Take it out, and the magic is gone!