I've used a Khozmo volume control/ "preamp" for several years now in two different iterations, and I would be hard pressed to go back to an active preamp despite having owned a few excellent ones through the years. Sonically, it's about as transparent as you can get and is the embodiment of simplicity. Build quality is top notch, and customer service from Arak (despite being in Poland) has been exemplary. My highest recommendation.
Hattor Audio preamps?
Got my eye on one of these. And yes, my system is passive friendly. I've had resistor based passives before, as well as transformer, autoformer and LDR preamps. So I know I like the sound quality which can be had with a passive. Anyone out there have any experience with the Hattor stuff?