6J1P-EV (6Ж1П-ЕВ) Tube

6J1P-EV (6Ж1П-ЕВ) Tube – EF95 / 6AK5 Equivalent, Long Life

The 6Ж1П-ЕВ (transliterated as 6J1P-EV or 6Zh1P-EV) is a Soviet-made miniature high-frequency sharp-cutoff pentode vacuum tube in a glass envelope with a 7-pin base (B7G / РШ4). It features an indirectly heated oxide cathode and was designed primarily for wide-band high-frequency voltage amplification in RF/IF stages, ultra-short wave equipment, television, and other radio-technical devices (including military and high-reliability applications).

The "-EV" variant indicates increased durability/reliability (E = enhanced longevity/reliability, V = high mechanical strength/vibration resistance). It is a ruggedized, long-life version with gold-plated grid and high-quality construction, offering a service life of at least 5,000 hours. It is a direct equivalent to Western tubes such as EF95, 6AK5, 6F32, 6J1, and CV850.

Key Specifications (nominal values unless stated otherwise)

• Filament (heater) voltage: 6.3 ± 0.6 V
• Filament current: 170 ± 15 mA (typically 172 ± 12 mA)
• Anode voltage (nominal): 120 V (limit up to 200 V in some modes)
• Anode current: 7.35 ± 2.35 mA
• Screen grid (g2) voltage (nominal): 120 V (limit 150 V)
• Screen grid current: ≤ 3 mA
• Transconductance (slope): 5.15 ± 1.25 mA/V (minimum > 3.4–4.25 mA/V)
• Anode dissipation (max): 1.8 W (derated to 1.2 W for long life)
• Screen grid dissipation (max): 0.55 W (derated to 0.4 W)
• Cathode current (max): 20 mA (derated to 13 mA for long life)
• Reverse grid 1 current: ≤ 0.1 μA
• Cutoff voltage (grid 1): ≤ –1.5 V (anode current cutoff ≤ –15 V in some references)
• Input resistance (at 60 MHz): ≥ 12 kΩ
• Equivalent noise resistance: ≤ 3.5–3.7 kΩ
• Interelectrode capacitances: – Input: 4.1 ± 0.6 pF (range 3.5–4.7 pF) – Output: 2.35 ± 0.45 pF (range 1.9–2.8 pF) – Feedback (through): ≤ 0.035 pF – Cathode-heater: ≤ 4.6 pF
• Dimensions: Height ≈ 48 mm, diameter ≈ 19 mm
• Weight: ≤ 15 g
• Base: 7-pin miniature (pinout similar to EF95/6AK5)
• Operating position: Any
• Service life: ≥ 5,000 hours (military/high-reliability grade)

It is often praised in audio applications (e.g., headphone amps, preamps) for its low noise and musical qualities when used in triode-strapped mode or as a pentode.