Audio Power Amplifier Triodes
The newly developed Svetlana SV811-10 series audio power amplifier triodes are intended for use in class A, AB, or class B amplifiers. The Svetlana SV811-10 series features a directly-heated thoriated tungsten filament for the warm sound and warm glow of this classic form of cathode. Thoriated tungsten filaments allow the SV811-10 series to handle overdrive at a cleanly defined level unlike commonly used oxide cathodes. Thoriated tungsten filaments are exceptionally stable and are not process sensitive. Therefore, unlike oxide cathode, their performance is much less adversely affected by overload. They also provide significantly better sound over a longer lifetime than oxide cathodes.
The internal tube parts are supported by ceramic insulators for high-temperature operation and high voltage hold-off. Stressed mica supports are used against the envelope to absorb vibration, thus controlling microphonic effects. The internal structure is aligned with respect to the base pins to avoid internal shorts if the tube is operated in a horizontal position.
Because these tubes are generally installed on the outside of high-end audio amplifiers, Svetlana manufacturing controls external mechanical and visual characteristics in addition to electrical characteristics. Further, Svetlana has incorporated a bright glazed white ceramic base which contributes significantly to the overall classic appearance of the SV811-10 series. A matching white glazed ceramic socket, the SK4, is available from Svetlana.
Svetlana now offers two new audio triodes from this series, the SV811-3 and the SV811-10, with amplification factors of 3.5 and 10 respectively. The nominal amplification factor is indicated by the type number suffix.