Is there any good hifi shop that deals with vinyl in your area? You may just want to bite the bullet and get someone who really knows what they are doing to set things up. The higher end tables like SOTA, Linn, Rega, etc etc are all very sensitive to setup. You need everything to be perfectly level, and then you need the cartridge properly set up, correct VTA, tracking force etc etc. Unless you get a kick out of that sort of thing, you might just want to spend the 50 bucks or however much and get someone to do it for you, and do it correctly. The advantage for me of buying from a local dealer was that he set the confounded thing up for me. It has sounded fantastic ever since.
That said, I HIGHLY recommend going out and picking up a high quality record. Get something from Classic Records or something like the Dark Side of the Moon hi rez spiffy remastered 40 pound super virgin vinyl sacrifice edition. If it sounds bad, then the problem is your table setup. Do you know who played the records before you? Chances are that they played them with a turntable that had a stylus like a back-hoe, and it could be that there just isn't any information for the SOTA to read.