Steve, I agree with what you say about the "source" singers. Every singer is a "source" of some sort, and any performance at any point in time is, as you say, just a snapshot. The material recorded from the older source singers (who are not the true sources of songs, simply singers of them) may well have been learned from the radio, or from a book or a ballad sheet, either by the singer or by the person whom they learned it from. I do listen to "source" recordings sometimes, but in other cases I find that the tune and the words become more alive for me in the hands (and voice) of a revival singer or song-carrier (if we want a different word for those born after about 1940).

Wherever I've acquired a song, I like to work on it by myself to make it my own without referring back to the original rendition. I'm aware that when some people sing, you can tell which singer they've learned the song from by the voice inflections and mannerisms they use. I prefer to try not to do this, and sing in my own voice and style. But that's a whole nother issue and probably best not explored in detail in this thread.

Marje