6J51P

 The tube 6J51P (6Zh51P, 6Ж51П rus.) is a high-frequency sharp-cutoff pentode designed for voltage amplification at intermediate frequencies in wideband amplifiers. It features an indirectly heated, oxide-coated cathode and is housed in a miniature glass envelope (B9A / Noval base). The tube was originally manufactured in the Soviet and is known for its low noise level and consistent electrical parameters. Works in any position.

Base: B9A (Noval, 9-pin).

Manufacturer: OCTOBER / NOS.

Full Electrical and Pinout Equivalent (Direct Replacement): EF184, 6EJ7.

Near equivalents: EF800, 6F28, 6F30, 3EJ7 (3.3 V heater), 4EJ7 (4.5 V heater).

• Stamp of technical control department of the manufacturer ” ОТК “ 

Technical specifications (at Uн = 6.3V, Ua = 200V, Ug2 = 200V, Ug3 = 0V): 

• Anode Current (Ia): 8.5 ± 2.7 mA
• Screen Grid Current (Ig2): 3.5 ± 1.5 mA
• Anode Cutoff Current (at Ug1 = -8.5V): ≤ 10 µA
• Transconductance (S): 15.5 ± 4 mA/V
• Inverse Grid Current (Ig1): ≤ 0.5 µA
• Internal equivalent noise resistance: 450 Ohm
• Input Resistance:  7 kOhm (at f = 40 MHz)
• Input Capacitance (Cin): 11.5 ± 2.3 pF
• Output Capacitance (Cout): 3.3 ± 0.7 pF
• Transfer Capacitance (Cgp): 0.0016 (+0.0044 / -0) pF (max 0.006 pF)

Limit values ​​of characteristics:

• Heater Voltage (Uн) 6.3 V (operates from 5.7V to 7V)
• Heater Current (Iн) 300 ± 25 mA
• Anode Voltage (Ua) 250 V (550 V when tube is cut off)
• Screen Grid Voltage (Ug2) 250 V (550 V when tube is cut off)
• Anode Dissipation (Pa) 2.5 W
• Screen Grid Dissipation (Pg2) 1 W
• Cathode Current (Ik) 25 mA max
• Heater-Cathode Voltage (Uf-k) ±100 V (positive), -150 V (negative)
• Ambient Temperature Range -60…+70 °C

Minimum operating time is not less than 3000 hours.