Paint by numbers not internal amplifier stages. It's more like A-S 30x to R-N800A, A-S 50x to R-N1000A (as it whose with R-N803) and probably A-S 700 ~800 line to R-N 2000A. Old R-N602 used really low end under the A-S/R-S 200 line which is let's say bare minimum of what you want and hopefully new R-N600A switched to that stage at least, old R-N402D used it. Neither of new line represents value. Gold in that segment is if you can find new with warranty A-S 700 for 500 $/€ or less (old stock) but that would be hard and second hand R-S or A-S 700 for 200~250 is also a great deal (as long as you don't mind second hand and that you will probably be able to find only black one's either new or second hand).