Soviet EL84 equivalent — same caveat as EL84: 6P15P has g3 on pins 1/6, 6P14P does not. Different ratings as well (6P14P is the true EL84 substitute).
EL83
Western video-output pentode with broadly similar electricals (mu ~57, gm ~12 mA/V) but different pinout and lower Pa_max (~9 W). Often cited as the 'Western equivalent' but it is not a true drop-in.
Same Noval base and the active pin positions match (g1=2, k=3, h=4/5, a=7, g2=9), BUT 6P15P brings the suppressor grid (g3) out to pins 1 and 6, while in EL84 those pins are unused and g3 is internally tied to the cathode. Plugging a 6P15P into an EL84 socket leaves g3 floating; for correct operation pins 1 and/or 6 must be strapped to the cathode externally. Operating points and screen ratings also differ (EL84 Vg2_max 300 V vs 6P15P 200 V).
Pinout differs from EL84/6P14P: in 6P15P/SV83 the suppressor grid (g3) is brought out to pins 1 and 6 instead of being internally tied to the cathode. The Svetlana datasheet notes that an EL84 may be used in an SV83 socket without modification (pins 1/6 are simply unused on the EL84), but the reverse is NOT automatic — installing a 6P15P/SV83 in an EL84 socket leaves g3 floating, which is generally tolerated but technically incorrect; tying pin 1 (or 6) to the cathode externally restores proper pentode operation.
Screen-grid maximum is only 200 V (1.5 W) per the Svetlana datasheet — substantially lower than EL84 (300 V). Do not exceed Vg2 = 200 V in audio designs.
Internally shielded for low hum pickup — useful in high-gain stages.
The -EV / -ЕВ suffix denotes a long-life / military-reliability quality grade of the same tube (5000 h+), not a different type.
Although Russian sources sometimes describe it as a 'video amplifier' tube, the SV83 export grade is marketed by Svetlana specifically as an audio power pentode suitable as a driver or small output device.
Maximum-rating values vary slightly between Russian (Va_max 250–300 V, Pa_max 12–14 W depending on source/grade) and Svetlana (Va_max 300 V, Pa_max 12 W) datasheets — the conservative Svetlana figures are used here.
Anode (plate) resistance ra = 30 kΩ is taken from the Russian primary datasheet (ORZEP/Orel); the Svetlana SV83 datasheet does not publish a numerical ra. For a pentode operating point this is the typical small-signal value at Va≈200 V, Vg2≈200 V.