The problem is that your preamp has high output and your amp has high sensitivity, the result being that you have little range in volume control. When this occurs, it has nothing to do with the "quality" of the components per se, and is merely bad synergy (like putting a guy who yells a lot with a women who cannot tolerate loud voices, or vice-versa)
I concur with the above comment, however, that if your volume range is from 6 O'Clock (off) to 1:00 O'Clock (full-blast), this is quite typical (I am tempted to say standard) and to me, not problematic. I once ran a CAT preamp with VAC amps and only had seven "clicks" on the volume control for range - 9:00 O'Clock was full-blast! I resolved the problem by selling the preamp in favor of a new preamp that had only half the output (gain) of the CAT preamp.
Good luck.