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A3 Transformer

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Electra-Print 300A3 Output Transformer -- Exclusive for the 300B Tube

Electra-Print Audio's new transformer is designed to offer A3 operation providing supererior performance over a stock 300B output transformer.

  • Lower Intermodulation Distortion gives higher undistorted peaks giving less audible congestion
  • Our circuit guides will be included for most popular 300B output stages to show the modifications needed with the 300A3 transformer.

    The 300A3 transformer is a combination of many inductive, reactive and capacitive functions designed to work with one tube, the 300B which will offer performance enhancements never achieved with this tube.


    Electra-Print Series 300A3 output transformers will be built with one output impedance and one secondary wire type, your choice:

    Prices (Electra-Print Series 300A3 output transformers will be built with one output impedance and one secondary wire type -- your choice)

    Output Impedance in OhmsType of Secondary WireTransformer Price Each (USD)
    16partial silver$759.00
    12partial silver$759.00
    8partial silver$720.00
    6partial silver$700.00
    4partial silver$700.00
    16solid silver$1500.00
    12solid silver$1400.00
    8solid silver$1300.00
    6solid silver$1250.00
    4solid silver$1200.00

    note: solid silver price is subject to change.

    6 and 12 ohm single secondaries are dual purpose; 6 ohms will match 4 or 8 ohms and 12 ohms will match 8 or 16 ohms. Custom secondary impedance also available.


    Electra-Print's new design 300A3 output transformers have the following features when compared to traditional designs

  • Lower tube generated even order harmonic distortion per given amplitude rise.
  • Lower intermodulation distortion (IMD) per given amplitude rise.
  • Lowest interwinding capacity of most standard SE outputs of this size.
  • Lower secondary to primary shunt capacity resulting in little or no distortion products generated from output tube.
  • Winding technique for least gradient winding capacity, resulting in a very high self resonance out of usable audio range.
  • Core material is M19, proven in all magnetically biased (plate current) devices, to offer the widest and most constant permeability resulting in less impedance change over the audio spectrum. Larger core mass used for less low frequency HD and IMD products.
  • Silver and partial silver windings offer a 200% increase in sensitivity over copper as a secondary, resulting in an increased in music detail or very low flux variations being induced as current. All transformer primary windings are solid copper.
  • Bandwidth of all transformers listed, is within -1db from 24Hz to 25kHz+ and power output is relative to circuitry parameters given, approximately 10 watts at clipping for standard 300B.


This Electra-Print transformer product is to be used for A3 operation of the 300B tube or its equivalent replacement. We have successfully tested the Sovtek 300B and Sovtek 6A3 tubes with this circuit. Tubes we used were able to have a measured 40 watt plus plate dissipation. Circuitry (below) is supplied to modify your amplifier output stage if needed, so that A3 can be obtained. Modifications to standard circuits will need to increase plate voltage and reduce plate current as indicated to obtain A3 operation.

Any failure of any tube after modification or components, due to higher voltages needed, are not the responsibility of Electra-Print company. It is assumed that purchaser of this product is fully aware of all aspects of electronics and has taken full responsibility of its proper application.

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