passive RIAA curve. Models include the II and the III. To augment the company's standalone phono preamplifiers, standalone line stage preamplifiers were introduced next, known as Linear Control Centers or LCC. One of the innovative features of the LCC was a bypass switch that permitted the user to select the use of an internal amplification module or straight into the potentiometer for volume control. Originally labeled 0 dB (line stage in) or -20 dB (passive only) this feature remained with all future PS Audio line stages and preamplifiers, later becoming labeled Straightwire in or out. With the advent of the III phono stage, the form factor moved from no faceplate to a small 8.5" rack style faceplate enabling owners to combine the two chassis into one unit, thus forming the first PS Audio preamplifier with phono input. This series marked the end of the first era of modular chassis approach to preamplification. Later preamplifier offering included the PS IV, the company's first 17" full chassis design and featured an external power supply for the first time in the American high-end audio industry. The IV featured a built in phono preamplifier with a novel switch on the bottom of the unit enabling users to select Moving Coil or Moving Magnet cartridges. Instead of adding in another circuit known as a head amp to increase the gain for Moving Coil cartridges, the IV took advantage of its passive RIAA curve design and simply increased the gain of the input amplification stage by an additional 30 dB. All future preamplifiers pre-1997 had this unique circuit that reduced the circuitry in the path of the phono cartridge. During the same era (late 1970s) PS Audio introduced its first power amplifier, the Model One, a solid state design producing 70 watts per channel into 8 Ohms and 140 watts per channel into 4 Ohms. The design was a classic AB amplifier design featuring the company's first full 19" chassis design, large power supply, low feedback and minimalist design constraints. The Model One was later followed with the world's first Audiophile integrated amplifier introduced by an American High-End company, the Elite. Based on the Model One architecture, the Elite integrated the Linear Control Center into a Model One amplifier chassis. The Model One was replaced by the Model II, moving back to a smaller modular chassis approach at 8.5" with faceplate. The Model II produced 40