You are absolutely right Jacquesboo, I realized this also while in a meeting 👍 but you beat me to it.
Powerlink is volume controlled line level, in addition it is actually possible to use the cable which the original poster suggest (also available from others) as a "powerlink to RCA" converter
if you on the other hand want line level, without volume control you should use the TV/aux connection on your 9300
so the most common cable with DIN -> 2RCA can be used for either line in from CD etc. to a beomaster. OR as powerlink "out" to an external amp. For line out of a beomaster aux (no volume controll) you need the less common cable with 4x RCA or one with 2RCA where it is specified that the audio signal is actually DIN->RCA (rare if you ask me)