Triode 6S33S-V High-Quality Russian audiophile tube. Used in Hi-End audio amplifiers. Designed to work as a regulatory tube in electronic voltage regulators
Low-frequency output tetrode 6P1P tube. Great sounding! Near equivalent: EL82, and similar to the 6AQ5, EL90, 6V6. Different pin out (9-pin base versus 7-pin base) than an 6AQ5, EL90
Russian tube 6K4P-EV - military-grade remote-cutoff pentode for HF amplification. Designed for RF and IF stages with automatic gain control (AGC) and vintage audio compressors. A direct, drop-in replacement for Chinese 6K4 (Shuguang) tube. Manufacturer: NEVZ (Novosibirsk) / NOS
Russian 6N1P-VI tube high-quality double triode. Low noise and microphonic effect. Optimised for "pulsed" mode of operation. Equivalent to the 6DJ8, ECC88, 6922