President, Gertrude Hull as Secretary, and Jess Oliver as Vice President. Growing pains and a changing market (1960―1967) In 1960, Ampeg introduced the B-15, a bass combo amplifier with an innovative flip-top function, invented and patented by Oliver. The B-15 was the first in the company's Portaflex series, and after becoming the preferred studio amp of session musicians like James Jamerson and Chuck Rainey. The B-15 and its subsequent variants went on to become the most-recorded bass amplifier in history. By 1963, the Portaflex series business had grown to 44% of Ampeg's amplifier sales. In 1962, Ampeg introduced the plastic-bodied Baby Bass, a compact upright electric bass created from the Zorko bass, whose design Ampeg had acquired from the Dopera brothers, along with a unique Oliver-designed, Ampeg-patented pickup. In 1962, Ampeg and its 40 employees moved to a new manufacturing facility in Linden, New Jersey. At 8,000 square feet, it was three times larger than their previous home. In June of the following year, after continued struggles to meet production demands and maintain cash flow, Ampeg announced an initial stock offering and became a publicly held company. By 1964, Ampeg had 100 employees and needed more space, relocating to a larger space one block away. The combination of the rising popularity of rock and roll and the shift of bassists from upright bass to electric bass guitar during this time posed a challenge to Ampeg’s core business. The company's ads continued to feature prominent classical, jazz, and country artists, but with a notable absence of rock artists, and Hull strove to minimize rock musician visits to Ampeg's facilities. Hull's distaste for rock and roll music was further compounded by the success of Ampeg's chief competitor, Fender, as they continually bested Ampeg in overall sales. Through the 1960s, Ampeg amplifiers were designed for "clean, undistorted sound", with Hull saying "we will never make anything for rock 'n' roll". The company continued to experience growing pains – by October 1966, with 200 employees and 40,000 square feet of space, Ampeg's production capacity had increased to $350,000 per month, yet had $3.5 million in unfulfilled backorders. Amidst company struggles related to growth and manufacturing, as well as disagreements with Hull, Oliver resigned from Ampeg. Hull began to seek potential buyers for the company. Ampeg enters the rock market (1967―1970) In September 1967, Ampeg became a subsidiary of Unimusic Inc. when the newly formed