If you are looking for older recordings, America may be a fruitful place: The Wisconsin Folksong Collection has field recordings form the 1930s and 1940s in many languages, reflecting the cultures that immigrants brought with them. All the singers were born in the 19th century - one as far back as 1858 - definitely not "revival" :-)

There are 16 Welsh language recordings there, and there may also be some songs in English sung by Welsh immigrants to Wisconsin.