I own the rhb10 power amp, rha10 active pre-amp and also the rhc10 passive pre-amp.
These are really high end units.
The rhb10 retaild in the us 2700 $$; the rha10 1500 $$.
I don't know how the rhc10 passive pre-amp retaild; i know it was sold around 600-700 sterling in england.
The power amp is a great machine, to my taste better then the bryston 4b-st for instance.
the active pre-amp is great too but notas the power amp.
The passive pre-amp is superb and is an excelent match for the mighty rhb10, better then the active pre-amp.
The only problem when using the passive pre-amp is that you have a gain loose and abit of dynamics loose so you have to use excelent interconnects and keep them as short as possible (half meter) and an excellent cd player with enough output voltage (2v).