I have had some experience with ML 38, 38S and 380S. They are all wonderful preamps. Highly recommended. The 38 series seems to do well with the stock power cord.
As for your cables, leanness usually indicates a problem with the speaker cables. If you are getting the high-frequencies with good focus, but it sounds a bit dry, this is usually the speaker cables. Good speaker cables may give you the lifelike "sparkle" and eliminate the granularity.
If the focus is not razor-sharp, then it is the interconnects. The IC's also give you bass tightness.
As for your cables, leanness usually indicates a problem with the speaker cables. If you are getting the high-frequencies with good focus, but it sounds a bit dry, this is usually the speaker cables. Good speaker cables may give you the lifelike "sparkle" and eliminate the granularity.
If the focus is not razor-sharp, then it is the interconnects. The IC's also give you bass tightness.