Welcome to Primary Windings

If you are looking for a valve transformer, whether you need a mains transformer, choke or an audio output transformer for your project, one that is built to last, and of the high quality  at a reasonable price, then Primary Windings is the place to come.

We are putting together a range of transformers for well known audio designs, starting with the Mullard 3-3 we have added the Mullard 5-10 . This year we will be adding the Mullard 5-20.

27/3/2019: Royal Mail Second class postage has been increased from £2.75 to £3.00.

  • Mullard 5-10 economic magnetics kit
  • Mullard 5-10 mains transformer with screen
  • Mullard 5-10 EL84 PP Output transformer
  • Maplin replacement 200V @ 50mA and 6.3V @ 1.5A
  • The popular PWHT01 2 x 250V @ 80mA 5V @ 2A 6.3V @ 2A CT


  • The Mullard 3-3, an excellent choice for a first amp - Although this was my second Mullard amplifier build, my first being the 5-10, this was quite an eye opener for me. Again I built to the Mullard layout for a control-less  amplifier, as described in the Mullard circuits for Audio amplifiers book.…
  • Transformer mountings – what they look like - One of the things that a builder should consider is the way in which he/she wants to mount the transformer. The terminology can be confusing, and inevitably ends in me sending a picture of a typical transformer mount to clarify…
  • Creating the Mullard 5-10 magnetics - 5-10 Output transformer From the start I wanted to create an output transformer for the Mullard 5-10, not as a cheap option, but a quality product that would allow a 5-10 builder, or any design using EL84’s in a push…