1608A-1650A Output Transformer Series

Author: Kevin M  Date Posted:15 April 2026 

Tube Output Transformers

Easy Wire Secondary Push-Pull Audio Transformers (10 to 280 Watts)
1608A – 1650A Series
Download Datasheet (PDF) View Legacy 1608 to 1650 Series Below

Design & Construction

  • Re-designed secondary windings for simplified load hook-up.
  • Designed specifically for push-pull tube output topologies.
  • Enclosed (shielded) Type "X" 4-slot above-chassis mounting.
  • Manufactured with high-grade plastic coil forms for superior support and insulation.
  • Minimum 8-inch flexible insulated leads for clean wiring.

Audio Performance

  • High-mass core design provides ample bass frequency headroom.
  • Full power frequency response: 30 Hz to 30 kHz (±1 dB max, ref. 1 kHz).
  • Secondary winding tapped for 4, 8, or 16-ohm impedance loads.
  • Supports Triode, Ultra-Linear Pentode, Pentode, and Tetrode audio connections.
Ultra-Linear Taps Note: All models in this series include 40% screen taps for Ultra-Linear operation, EXCEPT model 1650G. The 1650G does NOT have primary screen taps and will not support Ultra-Linear applications.

1608A – 1650A Series Technical Specifications

Part No. Audio Primary Max DC Secondary Dimensions (mm) Weight
Watts (RMS) Impedance (Ω) Per Side Impedance (Ω) A B C D E Slot G (lbs)
1608A 10 8,000 ct 100 mA 4-8-16 64 70 78 51 43 5 x 10 2.5
1609A 10 10,000 ct 100 mA 4-8-16 64 70 78 51 43 5 x 10 2.5
1615A 15 5,000 ct 100 mA 4-8-16 64 83 78 51 56 5 x 10 3.25
1650E 15 8,000 ct 100 mA 4-8-16 64 83 78 51 64 5 x 10 3.5
1620A 20 6,600 ct 158 mA 4-8-16 64 89 78 51 62 5 x 10 3.5
1650FA 25 7,600 ct 128 mA 4-8-16 64 89 78 51 62 5 x 10 4.0
1645A 30 5,000 ct 128 mA 4-8-16-70V 64 95 78 51 68 5 x 10 4.5
1650G 35 6,600 ct 200 mA 3.5/8/16/250/500 80 95 97 64 57 5 x 10 5.0
1650HA 40 6,600 ct 200 mA 4-8-16 80 102 97 64 68 5 x 10 6.5
1650KA 50 3,400 ct 318 mA 4-8-16 80 102 97 64 68 5 x 10 7.0
1650NA 60 4,300 ct 318 mA 4-8-16 80 108 97 64 75 5 x 10 8.0
1650PA 60 6,600 ct 200 mA 4-8-16 80 108 97 64 75 5 x 10 8.0
1650RA 100 5,000 ct 318 mA 4-8-16 95 108 116 76 78 5 x 10 12.0
1650TA 120 1,900 ct 403 mA 4-8-16 95 114 116 76 84 5 x 10 14.0
1650WA 280 1,900 ct 806 mA 4-8-16 111 191 133 89 149 5 x 10 28.0

Suggested Tube Configurations

Part No. Watts (RMS) Primary Impedance Suggested Push-Pull Tube Types
1608A / 1609A 10W 8,000Ω / 10,000Ω ct 6AQ5, 6V6, 6BQ5 / EL84, 6386
1615A / 1650E 15W 5,000Ω / 8,000Ω ct 6V6, 6BQ5 / EL84, 6L6CW, 6AQ5
1620A / 1650FA 20W – 25W 6,600Ω / 7,600Ω ct 6V6, 6L6, 5881, EL34, 6146B
1645A / 1650G 30W – 35W 5,000Ω / 6,600Ω ct 6L6, 5881, EL34, 807, 6146B, 6550
1650HA / 1650KA 40W – 50W 3,400Ω / 6,600Ω ct 2x 6L6GC, 2x EL34, 2x 6550, 2x KT88, 4x 6V6
1650NA / 1650PA 60W 4,300Ω / 6,600Ω ct 2x 6L6GC, 2x EL34, 2x 6550, 2x KT88, 4x 6L6
1650RA / 1650TA 100W – 120W 1,900Ω / 5,000Ω ct 4x 6L6GC, 4x EL34, 4x 6550, 4x KT88
1650WA 280W 1,900Ω ct 6x or 8x 6550 / KT88 / EL34 High Power Parallel Push-Pull