were heavier and more brittle.) 33s and 45s were, however, made exclusively of vinyl, with the exception of some 45s manufactured out of polystyrene. First all-transistor phonograph In 1955, Philco developed and produced the world's first all-transistor phonograph models TPA-1 and TPA-2, which were announced in the June 28, 1955 edition of the Wall Street Journal. Philco started to sell these all-transistor phonographs in the fall of 1955, for the price of $59.95. The October 1955 issue of Radio & Television News magazine (page 41), had a full page detailed article on Philco's new consumer product. The all-transistor portable phonograph TPA-1 and TPA-2 models played only 45rpm records and used four 1.5 volt "D" batteries for their power supply. The "TPA" stands for "Transistor Phonograph Amplifier". Their circuitry used three Philco germanium PNP alloy-fused junction audio frequency transistors. After the 1956 season had ended, Philco decided to discontinue both models, for transistors were too expensive compared to vacuum tubes, but by 1961 a $49.95 ($ in ) portable, battery-powered radio-phonograph with seven transistors was available. First direct-drive turntable The first direct-drive turntable was invented by Shuichi Obata, an engineer at Matsushita (now Panasonic). In 1969, Matsushita released it as the SP-10. the first direct-drive turntable on the market. The most influential turntable was the Technics SL-1200. Since then, turntablism spread widely in hip hop culture, and the SL-1200 remained the most widely used turntable in DJ culture for the next several decades. Arm systems Linear tracking Early developments in linear turntables were from Rek-O-Kut (portable lathe/phonograph) and Ortho-Sonic in the 1950s, and Acoustical in the early 1960s. These were eclipsed by more successful implementations of the concept from the late 1960s through the early 1980s. Pickup systems Additionally, cartridges may contain styli or needles that can be separated according to their tip: Spherical styli and elliptical styli. Spherical styli have their tip shaped like one half of a sphere, and elliptical styli have their tip shaped like one end of an ellipse. Spherical styli preserve more of the groove of the record than elliptical styli, while elliptical styli offer higher sound quality. Optical readout A few specialist laser turntables read the groove optically using a laser pickup. Since there is no physical contact with the record, no wear is incurred. However, this "no wear" advantage is debatable, since vinyl records have been tested to withstand even 1200 plays with no