Impedance Chart for Output Transformers

Impedance Reference Chart

Output Transformer Primary Load Matching Guide for Single-Ended & Push-Pull Valve Amplifiers
Please Note: This primary load impedance table is provided as a general reference guide only. Optimal primary load impedance depends on operating plate voltage, bias configuration, and target power output. Evatco accepts no liability for circuit design decisions made using this guide.
Circuit Configuration Primary Load Impedance (Ohms Ω)
18,000 14,000 10,000 8,000 7,000 5,000 4,000 2,000
Single Ended
Class A		 1F4 1J5 6G6 1C5 2A5 3B5 6AC5 2A3
1F5 1LB4 19 1G5 6F6 6AQ5 12A4 6Y6
  1T5 41 1Q5 12A 6L6 43 7A5
  10 49 1S4 42 6V6 45 25L6
  12A   3Q5 47 7C5 117L7 35A5
  12A7   3S4   12A5   35B5
  38   6K6   14C5   35L6
      6A4   50   48
      7A5   71A   50A5
      7B5       50B5
      12A6       50L6
      14A5        
Push Pull
Plate to Plate		   6K6 6AQ5 6V6   2A3    
  47 6F6 12A5   45    
    6L6 50        
    6V6 71A        
    42          
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