6С33С — 6C33C-B — 6S33S-V 6С33С — 6C33C-B — 6S33S-V Triode Vacuum Tube
High-power directly-heated triode for single-ended amplification
Michael Boele (compilation of Soviet documentation)
Rev 1.1, 2005-02-03 · 7 pp · EN
PRIMARY consolidated source. Seven pages covering nomenclature, mechanical data with Septar 7 pinout, filament options, typical operating point, full small-signal parameters with capacitances, service-life criteria, absolute maxima, environmental specs, extended-life de-rating tables, and the parallel-operation de-rating table for multi-tube banks. Defines the modern -B / -V notation (Russian: 6C33C-B / Western: 6S33S-V) and the high-reliability -EB / -EV variant (3000 h).
Penta Laboratories, Inc., Chatsworth CA
Penta Laboratories commercial sheet (undated) · 2 pp · EN
Western re-issue of the Soviet datasheet for the US replacement-tube market. Carries the canonical Class-A push-pull audio operating point used by Atma-Sphere / Graaf / BAT OTL designers: Va = 200 V, Vg = −65 V, Ia = 480 mA, Raa = 800 Ω, Wo = 55 W for two tubes. Also publishes Ia/Va curves at Ef = 6.3 V from Ec1 = 0 down to −100 V in 10 V steps (Ua 0–200 V, Ia 0–1000 mA), and announces Va max 400 V (slightly more conservative than the Soviet 450 V / Pa ≤ 30 W ceiling).
Soviet electron-tube reference book (publisher TBD)
Original Soviet справочник, p. 363–364 (translated) · 2 pp · RU
Original-source Russian datasheet for the base 6С33С (pre-B variant) covering: nominal Ia = 540 ± 90 mA, gm = 39 ± 11 mS, Ri ≤ 130 Ω, Cfk ≤ 70 pF, end-of-life criteria after 1000 h (Ia ≥ 340 mA / Igrid ≥ 15 µA), and the less stringent environmental envelope of the base type (vibration 4 g, shock 35 g, ambient −60…+70 °C). The -B / -V uplift figures (6 g vibration, 100–500 g shocks, +100 °C ambient) come from Boele's compilation, not this card.
| Capacitance | boele_b_variant | penta_labs | soviet_original_legacy |
|---|---|---|---|
| Cin | 30 pF | 30 pF | 30 pF |
| Cout | 10.5 pF | 10.5 pF | 10.5 pF |
| Cga | 31 pF | 31 pF | 31 pF |
| Cfk | 60 pF | — | 70 pF |
MU=3.27 EX=1.397 KG1=150.9 KP=13.94 KVB=300MU=2.67 EX=1.45 KG1=418 KP=14.6 KVB=5Ia vs Vg at Va = 250 V — each manufacturer Koren fit overlaid. The de-rated French families (μ=30) read lower than the Philips/1966 high-gm family (μ=32) at the same grid voltage.
Verbatim excerpts from the four manufacturer datasheets. Expand each section to read the original text — the Philips technical article carries the richest application content.
The 6C33C(2 cath) is a indirectly-heated triode from Svetlana · Ulyanovsk, introduced around 1960. It provides a gain factor (μ) of 2.7 with 69Ω plate resistance. Commonly used in otl / series regulator applications. Soviet power triode designed as a series-pass regulator (тube ballast) — two internal triode systems with paralleled anodes/grids/cathodes but separate filaments. Very low μ ≈ 2.7, very low Ri ≈ 80-120 Ω, transconductance gm ≈ 40 mA/V at 550 mA: the rare combination of low gain and high current that the OTL crowd (Atma-Sphere, Graaf, BAT, Lamm) bent the tube toward in the late 1980s. Built like a tank (200 g, internal bracing, oversized anode pin) with documented vibration/shock specs (6 g / 150-500 g for the -B/-V variant). Famously slow to reach thermal equilibrium (≥ 600 s) and prone to runaway if biasing isn't actively managed.