I had a Neuman M149 about 10 years ago for a few years. It's a great mic. The mic signal is quite strong and the needed gain from a preamp to get to recording levels is not much. Given that, a preamp that has an output attenuator, such as the Great River 2NV or Pendulum Audio MDP-1a, would allow for some variation in the amount of preamp gain applied, compared to the mic amp gain provided.

dont have any*Neuman M149's here: (