The 1392 amp was the next model up, and it had  almost everything you needed for serious sound customization: tone, tremolo strength/speed (and footswitch!), 3 inputs, and 10 watts into a nice 12" speaker. All that was missing was bass/treble controls... but tone would do for the price. Plug in and get your trem speed set to the tempo you're playin' that Bo Diddley beat and look out!

Introduced:
Fall/Winter 1957 at $67.95
as the 57D01391L

Retired:
Spring/Summer 1959 at $67.95
as the 57Y01392L