Not sure if this is your exact problem, but I had a similar issue reamping with Studio One and the 1810C - there was a feedback loop happening inside the 1810c that caused a squeal from the amp when I turned the recording level up. The problem was the Universal Control mixer software was allowing the feed back loop. I fixed it by opening Universal Control, opening the Mixer by clicking on the 1810c, clicking settings, and clicking bypass the mixer. Then everything worked fine.
Evidently studio one and the mixer software were conflicting. Another symptom was I could hear through the microphone without arming a track to record. Took a bit of trial and error to figure this out.