Strange, because I don't have the same problem. It may not be the converter. Is your transport an OPPO BDP-83 as well? Sorry if I missed your thread.
My Oppo is BDP 93 similar to this guy at post #29 where this is what he wrote:
"Plug and play DSD
Oppo 93 > Wireworld Silver Starlight > 2nd Gen naked board / printed box (new aluminum case looks sweet)>
generic HDMI 2.2 cable > D90 MQA w/original firmware
No additional 5V needed, instantly recognizes DSD signal "
Everything is playing fine with red book cd, blu ray or DVD Audio. Just that SACD!
Btw, do you have DTS cd? I have DTS cds however it wouldn't play via coaxial/optical although the website says it can play. Notice that some naked boards have 2.1 channels and 5.1 channels DTS, AC - 3 printed on the board. I attempted to play DTS cd and all I got is white noise. But I have another gadget which I have owned for several years and it will play DTS cd. So, I didn't bother using the IIS gadget to play DTS via coaxial.