Thanks, even with that facts, the RZ30 is, in my opinion a better choice for someone will only needs 5.1 and may have plan to expand to 9.1. That's because of the so called .2 vs the RZ50's .1. The RZ30 may have the lower spec DAC but even if it gets the PCM1690 or 5102A, it will still be good enough for people who don't have golden ears.
And, for someone like me who only want a preamp/dac for 2.2 stereo use, at the lowest price point (vs others), the RZ30 is as close as one can find, unless there exist a real 2.2 integrated amp or receiver but so far there is none, at least not within a $1,500 budget.
I don't know how Onko can do it at the $1,200 price point when D+M and Sony, who presumable have the advantage in terms of "economy of scale" cannot do, or at least have done it.