18W push pull output transformer
Designed for amps with a pair of EL84; 8k ohms primary
The latest version of this transformer is a direct clone of the transformer originally made by Danbury (who has since retired). That transformer came from my search for an output transformer for my PP-18 amp kit (a stripped-down version of the classic Marshall 18W amp of the ’60s). There were some British OTs available off-the-shelf (supposedly made for Marshall in recent years), but they seem designed down to a size – as if to fit into a 1U rack mount box – and they didn’t sound very good when the amp was pushed.
There were also several higher-cost US-made OTs for the 18Wer, including the Heyboer, which I liked (except for the cost of shipping and importing). We started by taking that Heyboer apart and making several variations on the theme. After a tone test, I settled on the best-sounding version (which happens to have grain-oriented laminations). It’s designed for use in a typical 2 x EL84 valve power amp, but would work fine in any push-pull output stage of 15-20W that requires an 8k ohms primary impedance. It has 8 and 16 ohm speaker taps. It’s clamp-mounting, with flying leads for connections.
Dimensions & info
Wound by a British company that also makes some of Amp Maker’s other transformers, this output transformer is 78mm wide, 64mm deep and 64mm tall. Fixing centres for the U-clamp mounting feet are 96mm apart. A great-sounding output transformer for classic 18W-based amplifiers Wire colour coding shown (right).