Ok thanks again for all the info. I did some google reading and realized that I used the wrong terminology in the topic of this post. My question shouldn’t have been about how to plug line level devices at all. Sorry everybody I’m learning…

It should have read “How do I plug a 1/8" unbalanced stereo into the 1/4" balanced input on the AR?

Am I correct in my understanding that all 1/8" stereo connections are unbalanced ? If they are, then it would make sense why Korg Volcas and my OP-1 are super quiet when I plug them into either the balanced inputs on my Presonus sound card or the input on the AR. I tried also using 1/8" TRS to 2x 1/4" TS on the sound card and its still quiet (peaks at like -12db with no gain). When I put gain on these instruments in my DAW they just end up sounding super hissey. I have the exact same issue when plugging the 1/8" TRS to single 1/4" TS on the Analog Rytm input except there’s no gain so it just stays quiet.

Could it be that I’m just using the wrong cables ? Is there such a thing as a balanced 1/8" stereo to 1/4" stereo cable ?