That doesn't sound right. My pair of OMs worked fine with Sonore's multimode transceivers/cables and single mode counterparts. They didn't sound right if mismatched (single mode transceivers and multimode fiber cable). But if matched, Sonore's multimode gear sounds good but Planet USA's single mode gear even better.I tried a pair of Sonore OM's and I couldn't get them to work in my system but for a few hours. It may be because I'm using single mode fiber and they designed the OM's around multi mode fiber. They did sound good while they worked but I'd advise only using multi mode with them.