I have owned EVS units in the past, so if your into passives his are the best. With only one Vishay resistor in the line you can't get more simple than that. That's why his cost are so low. I have stoped using them because after many years I had felt that the dynamics were lacking. I would be curious if some of these other units address this problem. Best and Good Luck.
Passive Preamps
I have the EVS "Nude Attenuator" RCA version which costs $225. I didn't evaluate others such as the Placette Audio, Art Audio, etc. My preference is the type that eliminated one interconnect and mounts directly to the back of the amp's RCA. Has anyone done cross comparisons between passive preamps? I have seen passive preamps as high as $1000. My system - Sony SACD player, Harmonic ProSilway II interconnects and a Bel Canto EVo 200.2 Digital amp.