Elvis’s first guitar player Scooty Moore had a costum made amplifier in the 50s that had a built in echo unit, the cabinet of this very amp is now for auction at eBay.

quote from eBay page:

The original Echosonic guitar cabinet used on most all the live and studio guitar work during Elvis Presley’s career (1955-1957).

You can hear it on all the hits from the early years including: Mystery Train, That’s All Right, Heartbreak Hotel, Blue Suede Shoes, Hound Dog, Don’t Be Cruel, Love Me Tender, All Shook Up, and more.

The Echosonic was designed and hand-built by Ray Butts. While only 68 ever being built, the Echosonic found a unique place in history with a built-in tape echo (loop) unit. …

This site has a very informative primer for Indorock newbies. Indorock is the closest equivalent to Surf western Europe had at the time (early 60s). It was performed by indonesian emigrants living in the Netherlands and touring western Europe, mainly the Federal Republic of Germany.

Here are The Tielman Brothers doing an Elvis vocal during the period the above picture was taken, with Fender Jazzmasters and Bass VI.