The EchoSonic is a guitar amplifier made by Ray Butts. It was the first portable guitar amplifier with a built-in tape echo effect, and it allowed guitar players to use slapback echo, which dominated 1950s rock and roll guitar playing, on stage. He built the first one in 1953 and sold the second one to Chet Atkins in 1954. He built fewer than seventy of those amplifiers; one of them was bought by Sam Phillips and then used by Scotty Moore on every recording he made with Elvis Presley, from the 1955 hit song "Mystery Train" to the 1968 TV program Comeback Special.[1] Deke Dickerson called the amplifier the Holy Grail of rockabilly music.[2]