Hi Matthew,
As is the case with the real box the converters are very quiet, but do produce a very small amount of noise and distortion. Convertors on/off allows you to turn that part of the model which adds the noise and distortion off.
There is also a small amount of pitch drift in the H910 which is independent between the two channels. This creates a nice stereo spread, but in come cases can cause image shifting. Pitch Drift Lock allows you to lock the pitch drift between the two channels so that it doesn't cause a stereo spread.
Dan
