6350

6350 has no equivalent designation confirmed by the archive. Completed sales put the typical price at $16.45 per tube.

The 6350 is a medium-mu twin triode of the 9-pin miniature type, designed for use in electronic computers and other 'on-off' control applications involving long periods of operation under cutoff conditions. It is particularly useful in pulse amplifier, inverter, frequency-divider, cathode-follower, and multivibrator circuits of high-speed digital-type electronic computers.

Construction

The 6350 incorporates a cathode made of special alloy material to minimize cathode interface, a protective shield to prevent deposition of getter material on micas and electrodes, radiating fins on the grids to increase dissipation capabilities, and a carbonized pure-nickel plate to minimize gas evolution. It has separate cathodes with individual base-pin connections. The tube uses a Small-Button Noval 9-pin base, JETEC No. E9-1. Maximum overall length is 2-5/8 inches, maximum seated length is 2-3/8 inches, and maximum diameter is 7/8 inch.

Heater

The 6350 has a pure-tungsten, mid-tapped heater arranged in series-parallel, permitting operation from a 6.3-volt or 12.6-volt supply. Heater voltage is 6.3 volts ±5% for parallel connection and 12.6 volts ±5% for series connection. Heater current is 0.6 amp for parallel connection and 0.3 amp for series connection.

Ratings and Characteristics

The RCA datasheet gives maximum ratings for the 6350 as follows: plate voltage (DC) 330 volts, peak positive pulse plate voltage 1000 volts, DC negative grid voltage 82 volts, and DC positive grid voltage 3.8 volts. At a plate voltage of 150 volts and a grid voltage of -5 volts, typical values are plate current 11 mA, transconductance 4600 μmhos, amplification factor 18, and approximate plate resistance 3900 ohms. When measured with 12.6 volts on the heater, 150 volts plate voltage, and -5 volts grid voltage, the amplification factor is between 15 and 21, and the transconductance is between 3200 and 6000 μmhos.

Capacitance values per unit are: grid-to-plate 3.2 μμF, grid-to-cathode-and-heater 3.6 μμF, plate-to-cathode-and-heater 0.6 μμF, and heater-to-cathode 4.6 μμF. Grid-to-grid capacitance is 0.042 μμF maximum.

Operating Features

The 6350 maintains its emission capabilities even after long standby periods, and exhibits a stable cutoff characteristic and freedom from grid emission.

Per-tube prices from completed sales, 2026-06-22 to 2026-09-08. Matched pairs and quads are divided out. See the price index for how these move over time.

Original manufacturer datasheets for 6350, hosted by Frank Philipse's Electron Tube Data sheets.

Documents held here and used to write this page.

• MEDIUM-MU TWIN TRIODE