thanks again. My converters are RME (Multiface + Fireface x 2). Now that you mentioned it, I think I am going to have to change the reference levels. They can be set to -10 dBv, +4 dBu and HiGain. Something tells me that they are set to -10 dBv, hence the clipping. If the clipping persists, I will get in contact with RME.
Maybe, high end converters like DAD or PrismSound will sound even better?