The 6N8S is a Soviet-manufactured, dual-triode vacuum tube produced by the renowned MELZ (Moscow Electric Lamp Plant) factory, featuring a distinctive metal base construction and the highly sought-after hole black plate design. This tube serves as a direct functional equivalent to the 6SN7GT, 6SN7GTA, and the legendary 1578 military-grade variant, offering exceptional linearity, low distortion, and superior sonic performance for high-fidelity audio applications.

Primarily designed for use in audio preamplifiers, driver stages, phase inverters, and voltage amplification circuits, the 6N8S is widely regarded as one of the finest dual-triode tubes ever produced. Its dual-triode configuration consists of two independent triode sections within a single glass envelope, allowing it to function as a two-stage amplifier or as a push-pull driver in vacuum tube amplifiers. The distinctive hole black plate design represents MELZ's highest manufacturing standard, delivering superior thermal management, reduced susceptibility to vibration-induced noise, and consistently stable electron flow. Beyond audio applications, it is also well-suited for use in oscillators, signal processing equipment, and various measurement instruments where stability and low noise are critical.

Technical specifications:

• Heater voltage: 6.3 V
• Heater current: 600 mA
• Plate voltage: 250 V (max)
• Plate dissipation: 2.75 W per section
• Amplification factor (μ): 20
• Plate resistance: 7.7 kΩ
• Transconductance: 2.6 mA/V
• Maximum grid voltage: -8 V
• Input capacitance: 2.8 pF
• Output capacitance: 2.4 pF
• Minimum operational lifespan: 1000 hours