6AW8A

The 6AW8A combines a high-mu triode and a sharp-cutoff pentode in a small nine-pin envelope. General Electric and Tung-Sol assign the triode to sync separation and the pentode to video amplification in television receivers. RCA's manual adds IF, video, automatic gain control and reactance applications for the pentode; low-frequency oscillator, sync separator, sync clipper and phase splitter applications for the triode. These are two systems in one envelope with separate cathodes and signal connections. GE specifies that the A suffix denotes a controlled plate-knee characteristic for the pentode, distinguishing it from the 6AW8.

The heater requires 6.3 V at 0.6 A and has controlled warm-up, intended especially for 600 mA series heater strings. Tung-Sol explains that this feature limits voltage surges during warm-up when used with other types whose thermal behaviour is similarly controlled. The stated 11 seconds is defined by a specific test reaching 80% of rated voltage; it is not a universal equipment settling time. The 8AW8A is listed as identical in its electronic systems, but with an 8.4 V, 0.45 A heater for a different series string.

At the triode's characteristic point of 200 V plate voltage and −2 V grid voltage, RCA and GE specify 4 mA, amplification factor 70, transconductance 4 mA/V and internal resistance 17.5 kΩ. For the pentode, 150 V at plate and screen with a 150 Ω cathode resistor gives 15 mA plate current, 3.5 mA screen current, 9.5 mA/V transconductance and about 200 kΩ internal resistance. The factor 70 belongs to the triode, not the gain automatically achieved by any circuit. An important detail is the internal shield, connected to the pentode cathode and suppressor grid: RCA recommends low cathode-circuit impedance to reduce coupling between the systems. Its sheets show maximum plate-to-plate capacitance falling from 0.150 pF without an external shield to 0.025 pF with the specified shield.

The data editions retain ratings expressed under different systems. GE's September 1957 sheets use design-center values: 300 V plate voltage and dissipation of 3.25 W for the pentode and 1 W for the triode. The April 1963 revision uses design-maximum values: 330 V and respectively 3.75 W and 1.1 W, agreeing with RCA's 1962 sheets. These numbers must not be combined into a new specification. Screen supply voltage is also distinct from actual screen voltage and permissible grid dissipation, described by a separate curve. The base carries triode cathode, grid and plate on pins 1, 2 and 3, heater on 4 and 5, pentode cathode, suppressor and internal shield on 6, and its control grid, screen grid and plate on 7, 8 and 9.