These are perhaps the most notorious of all Rickenbacker amplifiers; featured in the 1968 Rickenbacker catalog, they were used by several popular rock groups in the late ‘60s and early ‘70s. The larger brother to this amp is the Transonic 200, which features a separate head and a speaker cab mounted on a metal trolley (think Vox Super Beatle), and a little brother, seldom seen, the Transonic 70. All have the reverse-triangular/trapezoid shape. I can say from personal experience that, because Rickenbacker loaded the transformers and other internal hardware for this amp on a 3/16” sheet of plywood, this amp is a bear to travel with or to ship. It has all manner of knobs and buttons and two 12” heavy-duty Utah speakers.