AC30TB

The Vox AC30TB, or “Top boost,” is the definitive version of one of the classic tube guitar amps. While the AC30, was introduced in 1958, it was the 1960s version with its added Top Boost (also known as the “brilliance”) circuit, which added an additional gain stage and tone controls for bass and treble, that became the Vox AC30 known and loved to this day. The GZ34 rectifier tube used in the late ’50s and ’60s was replaced with a silicon rectifier in the 1970s, but few changes have been made to the basic amplifier circuit since.