Second some from Tom Russell. I'm not familiar with all his work but I have and really like "The Man From God Know's Where" and "Modern Art," very well recorded and good tunes, but "Hotwalker," while very interesting and a good listen, is more of a spoken word narrative that you would not listen to very often. Worth a listen but borrow a copy or buy it used.
John Prine's albums are usually very well recorded. The early stuff on vinyl is very good too.
David Grisman and Jerry Garcia put out a series of folk/blugrass/country/old time music albums that are very good.
We showed you ours now you show us yours Canuck.
Doc Watson. Let me repeat that, Doc Watson. Everything I have is on vinyl but some of the finest music ever recorded and some are very high fidelity. The finest flat picker on the planet and compelling vocals. Buy all that you can find.
Guy Clark is usually listed in the country section but I would call him a singer/songwriter in the folk tradition. A true genius with the pen and a great performer. Start with "Boats to Build" for great songs and sonics. His duets with Emmylou Harris are mesmerizing, most duets with her are. One of my favorite albums of all time.
Townes Van Zandt, maybe not show off your stereo fidelity but great, great music. The 4 CD set "Texas Troubador" has 8 of his albums and pretty much covers his best work.