6s33s (Cyrillic 6С33С)

Two of these are often used in a Push Pull Audio Amp. There is a version without the 2 or 3 pips on top. In Russian (Cyrillic)  6С33С

Triode with a small gain. Designed as a regulator tube in electronic voltage stabilizers. Developed and prepared for release in the late 50's in the union, "Svetlana" Leningrad. At the same time launched a series of triodes of a family of  tube regulators 6s41s, 6s19p, 6s47s, 12s42s. In the early 70's there was a version 6s33s-v - high reliability. Clone has normal reliability - 6s18s, balloon which has no projections (two or three) at the top. For electrical characteristics and the 6s33s and 6s18s are identical. By the mid-70's production of 6s33s fully translated (moved to?) in the Ulyanovsk plant [for] vacuum devices, now the only  known manufacturer 6s33s.

The tube has a 7 pin base, anode pin 4 thicker than the others, is key. A special Ceramic socket with silver contacts is needed. There is also a panel on the PL3-1PD, but because of the heat cap (40 watts of power allocated to the heater filament) to apply it is not recommended. It is more suitable for 6S41S.

As for audio applications, using the tube in "Push Pull" requires special approaches. Need a transformer with the primary, normalized to the current 200-250 mA, with impedance between the anode is less than is usual - 1-1.2 ohms [K?]. However, at such high currents, quiescent (120-150 mA), it is difficult to keep the balance of the output transformer. Even a small imbalance (5-7 mA) immediately throws it into saturation. But the winding 1.0 - 1.2 [K?] ohms in the primary - the work relatively easy, the conversion coefficient for the 11-13 8 ohm load.
There are output transformerless design (OTL), and single-ended.

 

The main electrical parameters

From the databook/Journal/Directroy  [?] "Приемно-усилительные лампы повышенной надежности." Ed. "Soviet Radio" 1962)

 

[Translated badly from a Russian website, Google "6С41С, 6С19П, 6С47С, 12С42С"]

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