leftover AB763 (blackface) tube charts left over well into 1969 and shipped these charts with silverface models. Silverface Fender Silverface amplifiers were built between 1967 and 1981. They are often referred to as Silverface or Chromeface because of their brushed aluminum face plate. The first Silverface amps, manufactured between 1967 and 1969, had an aluminum frame trim, known as a "drip edge" around the grillcloth. a "tailed" amp logo and the AB763 blackface circuit. An even rarer feature were the vertical, narrow black lines, which separated knob groups in the control panel. This cosmetic detail (later referred to as "blackline") was quickly abandoned. All of the Silverface amps generally had blue labels on the face plate, but in some rare exceptions (such as the Bronco) the colour was red instead. Some transitional models produced before the "tailless" period in 1973 featured the AC568 circuit. In 1973 CBS changed the "tailed" Fender amp logo to the modern-looking "tailless" style (which was first introduced in 1967 on the student Bronco amp). A master volume knob and a pull-out "boost" pot were added on some amplifiers, followed by ultralinear output transformers and a "scripted tailless" amp decal featuring a "Made in USA" script in the bottom. Additionally in 1977, the power was increased between 70 and 135 watts on certain models. All Silverface models usually came with a sparkling silver/blue grillcloth (some later models had a non-standard sparkling silver/orange grillcloth, and a black grillcloth was even fitted to some production runs). The Silverface control face plate was discontinued in 1981 and replaced by the second series of the blackface amps. In 2013, Fender released the silverface '68 Custom amplifiers as a part of their Vintage Modified series, modeled after the original drip-edge silverfaced amps of 1968. Models included the Twin Reverb, Deluxe Reverb, and Princeton Reverb, and a Vibrolux Reverb was added to the line the following year. Each amp incorporates reverb and tremolo on both channels. Other features include a Custom channel (which has a modified Bassman tone stack giving modern players greater tonal flexibility with pedals), quicker gain onset and reduced negative feedback for greater touch sensitivity. The single-channel Pro Reverb and Vibro-Champ Reverb combos were introduced in January 12th, 2021. Early solid-state models Fender's first transistor amplifiers were introduced in 1966. At the time they were the company's "flagship" range and aimed to make the tube-based designs obsolete. The amplifiers