Seventy years ago, this aspiring musician was able to play the electric guitar thanks to the three-tube amplifier she constructed from plans in the January 1956 issue of Popular Electronics.  In addition to use as a guitar amp as shown here, it could be used as a phonograph amplifier, or simply as a general-purpose amplifier in the lab.

It was built on an aluminum chassis made of soft aluminum that could be cut with ordinary household shears.  A speaker baffle formed the cabinet.