Thanks. I see that there isn't much help... RB433AH ana SR5 is quietest combination (both MikroTik cardshave 4R7 power incuctor witch makes noise, and RB600A is louder for some reason), I'll stick to that.
I have the same problem. Tried with RB433AH, RB600A, SR5, R5H and R52Hn. Any combination of board and card makes noise. Also tried different power supplies (12, 24 and 48V), no difference. Is there a solution, since I'm sleeping in that room?