These two dudes look like they stepped out of the boardroom to pull off a tight little rendition of Blind Boy Fuller’s “Step It Up and Go.” As far as I can tell, the washboardiste is Jack Amblin. He plays his board à l‘américaine with thimbles. His board looks to be rigged out with a bicycle bell, a tin can or cup, a very tiny splash cymbal, a high jam block, and, possibly, a little woodblock on the top.
He has a nice straightforward style that fits well with Roper’s steel guitar stylings.
You can learn more about Jack here.