Watch the Tools: Amps & Effects online guitar lesson by BJ Baartmans from Slapback, Billy & Twang Guidebook
In the late 50's and early 60's, most guitar players worked with a very basic approach to amplifying their instruments. The main reason for this is that there were hardly any effect pedals around. No fuzz boxes, overdrives, modulation, or wah wah devices in store.
Some effects were available though, and they were certainly put to good use, like tape delay, tank reverb, and amp tremolo. Players like Bo Diddley, Scotty Moore, or Dick Dale are certainly associated with an electronically tweaked sound.