Distortion/clipping out of mains out, but not headphone out

  • Hi,
    I'm using several patches that sound clear and great out of my headphones, but they sound like they are clipping or distorting when used through the main left/right outs into my Universal Audio Apollo soundcard and out to my monitors. I checked the signal and it peaks at -10 db, so I'm not close to clipping the pre amps and the led in the sound card's mixer isn't anywhere close to red. Any advice is greatly appreciated.