As Stereojack says, the most tracks are from 1947 and one has to count in the technical abilities and the studio equipment during these times. That makes to music sometimes sound thin and harsh, especially for the drums. Besides that, the record itself (I refer to a Lexington, DG, Flatedge-pressing)has a nice sound and I would think, that the 10"es sound worse.
You should check the different sessions, because they all sound different. The sessions from 1952 have the best sound (especially "Four In One" and "Straight, no chaser", while the Trio-track from 1947 sounds the worst ("Nice work").