DIY Audio Transformerby Thomas Edward
Most audio transformers are integrated into an audio system such as a high fidelity or power amplifier. Many DIY kits use high-technology circuits to deliver a near flat response over the audio spectrum. A DIY audio transformer is a challenge. The addition of an audio isolation transformer with a 1:1 transformation ratio will provide wide-frequency bandwidth, low distortion, and high-noise suppression. An audio output transformer for a tube amplifier can be built for under $5 with an evenings work. (See the Resource section for tips to design and wind an audio output transformer.)
DIY Audio Isolation Transformer
Obtain two audio transformers with a 1:1 transformation ratio and an impedance of greater than 1,000 ohms. Quality audio transformers with these specifications are expensive. As an alternative, use 600:600 ohm isolation transformers similar to those used in telecommunication equipment. (See Reference.) This addition will help minimize distortion and reduce noise–and then you'll have an audio signal with good clarity and definition.
DIY Audio Output Transformer for a Guitar Tube Amplifier
In an evening you can build an output transformer to drive a Fender Deluxe guitar amplifier using 2 6V6 output tubes in a push-pull circuit. This amplifier would produce about 15 watts. (See Reference.) A detailed transformer winding plan is included with drawings and recommendations to make the project easier. Output transformers are the most costly component in the amplifier. If you master this technique, you could possibly sell copies to rock star hopefuls and guitar enthusiasts for a profit.