Sylvania Electric Products was an American manufacturer based in Emporium, Pennsylvania, that became one of the most significant vacuum tube producers of the 20th century. Originally formed from the Hygrade Lamp Company, Sylvania began producing vacuum tubes under RCA license in 1924 and grew into RCA's primary domestic rival, earning a reputation as the second-largest receiving tube manufacturer in the United States. The company merged with General Telephone in 1959 to form GTE, and its tube operations were eventually sold to Philips, which continued to produce Philips ECG valves at the Emporium plant until it closed.

For guitarists and audio enthusiasts, Sylvania's legacy rests on its preamp and power tubes, which remain highly sought after on the vintage market. The company's 12AX7 preamp tubes — produced in multiple variants including the noted short black plate design of the mid-1950s — are prized for a sweet, musical midrange, clear but unharsh treble, and substantial low-end response. Power tubes such as the 6L6GB, 6V6, and 5U4 rectifiers are commonly found in vintage Fender, Gibson, and other American-made amplifiers of the 1950s and 1960s, and Sylvania also produced octal dual-triodes like the 6SN7 that are widely used in hi-fi and studio gear.

Sylvania tubes were frequently rebranded for other manufacturers during the golden era of American tube production, and genuine NOS Sylvania stock is a staple offering at specialist dealers serving the guitar amp and audiophile communities. While the original tube-making operation is long out of production, Sylvania-branded valves continue to circulate through the vintage and boutique amp repair market.

Sylvania has 1 product cataloged on Equipboard, including Guitar Amplifier Tubes.