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Eimac 4-400A High-Vacuum Power Tetrode Transmitting Tube, Box & 1966 Return Form

Currency:CAD Category:Electronics / Vintage Electronics Start Price:10.00 CAD
Eimac 4-400A High-Vacuum Power Tetrode Transmitting Tube, Box & 1966 Return Form
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[?]Live Online Auction Starts In 2026 Oct 13 @ 10:00 (UTC-07:00 : PDT/MST)
Preview: October 10th (10am - 5pm)
Pick ups: October 14th - October 16th (10am - 5pm)

Preview and Pick up location: 27294 Fraser Hwy, Aldergrove, BC V4W 3P8

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Eimac type 4-400A high-vacuum power tetrode manufactured by Eitel-McCullough, Inc. The transmitting tube has a clear glass envelope, top contact, five-pin perforated metal base, and internal plate structure. Red envelope markings read "Eimac," "4-400A," "Made in U.S.A.," and "620." Includes a yellow corrugated Eimac carton and an Eitel-McCullough tube return form completed for serial number 12-6646. The form records purchase in July 1966 and use by CKX in a Gates 1 kW AM radio station as an RF driver at 1150 kc, with 11 hours of filament operation and air cooling. It reports that the tube would not accept plate voltage without triggering the thyratron and is dated July 20, 1966. Manufacturer specifications identify the 4-400A as a power tetrode with a 5-volt, 14.5-ampere thoriated-tungsten filament and maximum ratings of 400 watts plate dissipation, 4,000 volts plate voltage, 600 volts screen voltage, and 350 milliamperes plate current. The specified cooling method is radiation and forced air.

Maker: Eimac / Eitel-McCullough, Inc.
Model: 4-400A
Type: High-vacuum power tetrode transmitting tube
Tube markings: Eimac; 4-400A; Made in U.S.A.; 620
Base configuration: Five-pin perforated metal-shell base with top contact
Filament rating: 5 volts, 14.5 amperes
Maximum plate dissipation: 400 watts
Maximum plate voltage: 4,000 volts DC
Maximum plate current: 350 milliamperes DC
Cooling: Radiation and forced air
Documentation date: July 20, 1966
Documented station and equipment: CKX; Gates 1 kW AM radio station
Documented service: RF driver at 1150 kc; 11 filament hours
Included components: 4-400A tube, Eimac carton, and completed tube return form
Condition: As pictured.