I'm not a big fan of the "no preamp" school of thought. But I have had all manner of active and passive preamps come through my room and I am convinced that a well thought out system will benefit from some type of very good passive device. I've had autoformer, transformer, and conventional resistor based preamps but my favorite is something like the Tortuga Audio using light dependent resistors. This is about as close as you can get to no preamp, but solves the issues with component impedance mismatches.
The take away is when you have sensitive, easy to drive speakers, enough source gain, and components that play well together, a good passive preamp is hard to beat.