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Amperex 3-400Z / 8163 Power Amplifier Tube Tested Full Output S/N 434587 date code 6740

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MPN:
3-400Z
Condition:
Used
Shipping:
$14.00 (Fixed Shipping Cost)
  • Amperex 3-400Z, 8163 tube, vintage power triode, NOS 3-400Z, Ameritron AL-80, tantalum anode, made in USA, 1967 date code, ham radio tube, Nationwide Radio & Eq Sales LLC
  • Amperex 3-400Z, 8163 tube, vintage power triode, NOS 3-400Z, Ameritron AL-80, tantalum anode, made in USA, 1967 date code, ham radio tube, Nationwide Radio & Eq Sales LLC
$174.99
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Description

Amperex 3-400Z / 8163 Power Amplifier Tube Tested Full Output S/N 434587 date code 6740

 I tested this 3-400Z, in an Ameritron AL-80 Amplifier and it is performing at full output.

date code 6740 indicates it was manufactured in the 40th week of 1967 at the Amperex factory in Hicksville, New York. Tubes of this era are among the best made.

Tube Information & History
  • Manufacturer: Amperex (USA), widely considered the "gold standard" for 3rd-generation power triodes.
  • Design: High-mu power triode with a tantalum anode. Tantalum thrives on heat; the redder it glows, the better it "gets" (absorbs) residual gases.
  • Compatibility: Directly interchangeable with the 3-500Z, though it has slightly lower plate dissipation (400W vs 500W).
The Amperex 3-400Z (8163) is a high-mu power triode designed specifically for zero-bias Class B operation in grounded-grid radio frequency applications.
 
Physical Specifications
  • Anode Material: Tantalum (requires "red heat" for gas absorption).
  • Base: 5-Pin Special (fits Eimac SK-410 or similar sockets).
  • Cooling: Radiation and forced air (vertical mounting preferred).
  • Envelope: Hard glass (Nonex).
 
Electrical Characteristics
  • Filament Voltage: 5.0 Volts (AC or DC).
  • Filament Current: 14.5 Amps (± 1.0 A).
  • Amplification Factor (
     
    ): 200.
  • Direct Interelectrode Capacitances (Grounded Grid):
    • Input: 7.4 pF
    • Output: 4.1 pF
    • Feedback (Plate to Cathode): 0.07 pF
 
Maximum Ratings (Class B RF Linear Amplifier)
  • DC Plate Voltage: 3,500 Volts (Max).
  • DC Plate Current: 250 mA (Max).
  • Plate Dissipation: 400 Watts.
  • Grid Dissipation: 20 Watts.
 
 
Operating Performance (Typical)
At a plate voltage of 3,000V, you can expect the following typical performance in a grounded-grid configuration:
  • Zero-Signal Plate Current: 50 mA.
  • Max Signal Plate Current: 250 mA.
  • Driving Power: 30–50 Watts.
  • Power Output: Approx. 500 Watts (PEP/RMS).
 
 
Comparison Note: 3-400Z vs. 3-500Z
  • Interchangeability: They are pin-for-pin compatible.
  • Drive Power: The 3-400Z is slightly easier to drive than a 3-500Z.
  • Heat: The tantalum anode in your Amperex must glow dull red during operation to maintain its vacuum integrity (the "getter" action).
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