He may say that JC was his first mentor, but I have found the truth.
On eBay is the amplifier on a cart true inspiration of Mr. Slagle. The text said it belongs to a 90 year old ham radio operator, so it clearly predates Dave's New York Noise work.
RCA New Dimension In Sound 1957 - What is Hi-Fi from the Smith's and RCA. http://www.itishifi.com