If all you want to do is match the preamp gain to the amp sensitivity you don't need a continuous control like a pot (may affect audio quality) or a stepped attenuator (expensive). All you need is a couple of resistors (dividing network). Use some cheap resistors from Radio Shack to determine the values you need, and then substitute exotic resistors, of the same values, if you think it matters.
Don't worry about "overloading" the power amp input. Your use of the preamp volume control prevents that. The disadvantage of too-high preamp gain is that the volume control will be very low down in its range. Working near the top of its range is good both with regard to audio quality and user convenience.
Don't worry about "overloading" the power amp input. Your use of the preamp volume control prevents that. The disadvantage of too-high preamp gain is that the volume control will be very low down in its range. Working near the top of its range is good both with regard to audio quality and user convenience.