Audio, Coupling, & Telephony

Prem Magnetics designs and manufactures a wide variety of high quality transformers, including audio transformers, telephony transformers and coupling transformers.

Audio Transformers

Audio transformers are designed to match impedances from input to output over a specified audio frequency, most commonly 20Hz to 20KHz. The size of the unit will depend on its output power, impedance value, distortion (quality), and frequency response. Audio transformers can be found in a wide range of audio equipment, including microphones, loudspeakers and amplifiers. Prem Magnetics has many different types of audio transformers available for purchase. We also design and build custom audio transformers to exact specifications for unique applications.

Coupling Transformers

Coupling transformers are used to match impedances of a specific value as required by the equipment in which they are used. In the past, coupling transformers were commonly used in dial-up internet modems that operated on a bandwidth of 200Hz to 3KHz, over telephone lines. Coupling transformers are used for radio and television broadcasting applications, and this remains one of their most common uses today. Coupling transformers can be designed to meet the needs of equipment requiring different frequency bandwidths and power. Our wide variety of coupling transformers includes safety-critical coupling transformers, shielded coupling transformers, gull-wing style surface mount coupling transformers and more.

Telephony & Line Isolation Transformers

Telephony transformers, also known as line isolation transformers, are used to connect telephone lines to residential, business and emergency dispatch equipment.

Telephony transformers typically have a 600Ω input impedance, from the telephone line. A line matching transformer matches the impedance between two lines (such as a power amplifier to speakers for a public address or intercom system).

The telephony transformer is just one type of impedance matching transformer. Line matching transformers tend to have various impedance parameters depending on their application.

Telephone Transformers

As the name suggests, telephone transformers are used in telephone applications. Telephone transformers makes use of a simple input/output, where the transmit-and-receive function is carried by the same windings.

Telephone Hybrid Transformers

Telephone hybrid transformers are also used in telephone applications, but use a different method of impedance matching. A telephone hybrid transformer allocates the transmit-and-receive function on the telephone line (central office) side, and then splits the transmit-and-receive functions to two independent windings on the Secondary side.

Telephone hybrid transformers can be accommodated on a single core, also known as a single hybrid, or on two independent cores, known as a dual hybrid, to allow for better transmission.


Our telephony, coupling and audio transformers are ideal for matching impedances while providing isolation and maximum power transfer between devices or lines. Prem Magnetics is known for manufacturing dependable, reliable audio transformers. These products are thoroughly tested so customers like you can trust their reliability. If you don’t find an audio transformer that meets your exact specifications, contact Prem Magnetics for custom services. Our expert team will design and manufacture an audio transformer that meets your needs.