This also depends on how you are running the LSS. The effects loop adds an extra gain stage that can also be overdriven, so the position of that knob in the back has a big impact on how much headroom you have. Many players, myself included, like to run the effects loop volume at the "+" sign, about 1:00 on the knob. This will limit your clean headroom somewhat, but also brings the drive channel to life at lower volumes. If you disable the effects loop (which also disables the overall master and solo knobs - which is why I don't do it), it becomes a much louder and cleaner amp. Lowering the effects send knob has a similar effect, but not as pronounced as its still running through an additional gain stage.