All You Would Want To Know About Audio Transformers

A transformer is an electrical device that allows an AC input signal to produce an AC output signal without the input and output being physically connected. This device works with two or more coils of insulated wire, called windings, wound around a magnetic metal core. When an AC signal passes through the primary winding, which is the input, a related AC signal appears on the secondary winding, which is the output. This entire procedure is known as inductive coupling.

All You Would Want To Know About Audio Transformers - Miracle Electronics

Transformers can be manufactured with multiple primary and secondary windings, each with multiple connections or taps that offer different impedances. Transformers with various impedance ratios can be manufacturing by altering the number of wire turns in each winding. As the signal passes through the transformer, the ratio between the input and output impedances provides a gain or loss of signal level. Since transformers are bi-directional in nature, they can provide a gain in signal level when used in one direction, and a loss in signal level when used in reverse.

With a wide variety of transformers available, we will only focus on audio transformers, their usage, their types, and more in this blog. Audio transformers are those that are designed for usage in amplifiers and high frequency audio/video circuits for coupling and impedance matching applications. There are two main types of audio transformers – step-up/step-down transformers, and unity 1:1 transformers.

Step-up / Step-down transformers

Step-up and step-down transformers have different number of windings in the primary and secondary, thus leading to different impedances that ultimately cause the signal level to change. If the secondary has more windings as compared to the primary, the impedance will be higher and the signal level will be at a higher voltage too. Transformers with multiple taps provide access to multiple impedances and different signal losses/gains. The two main functions of step-up/step-down transformers are signal level compatibility or matching, and impedance compatibility or matching.

Unity 1:1 Transformers

Unity 1:1 Transformers have the same number of windings on each coil, which means identical impedance for both primary and secondary, therefore leading to no change in the signal level. Such transformers allow an audio signal to pass unaltered from the primary to secondary while blocking DC voltage and radio frequency interference. The quality of unity 1:1 transformers electrically isolating different pieces of equipment, results in solving noise issues. The main functions that unity 1:1 transformers perform include DC blocking, radio frequency interference blocking, ground lift, and device isolation.

What are the benefits of audio transformers?

After reading the blog above, you are well-versed with all the benefits that audio transformers provide. However, to sum it up, here is the list. Audio transformers can increase or decrease a signal voltage, increase or decrease the circuit impedance, convert circuits between balanced and unbalanced, block DC current while allowing AC to flow, and electrically isolating one device from another.

What are the limitations of audio transformers?

Even though audio transformers provide such amazing benefits, they also come with a lot of limitations, some of which are stated below.

•      Audio transformers can only pass audio signals, meaning that they reduce or block signals below and above the audio range of 20 to 20,000 Hz.
•    Audio transformers have maximum input level that can’t be exceeded without causing distorted signals, meaning that when the maximum level is exceeded, they can’t hold any more signals.
•      Audio transformers can’t step up signals by more than 25 dB when used in audio circuits; thus requiring an active pre-amplifier for a gain of more than 25 dB.

 Consequently, you can use audio transformers to match impedances, increase/decrease signal levels by up to 25 dB, and isolate problem components within an audio chain. However, when you need to increase a signal level by more than 25 dB, audio transformers are inappropriate solutions. Miracle Electronics is a leading transformermanufacturer in India, whose audio transformers can help you hear better with no disturbance in your auditory pleasure because the impedance of loudspeakers can be matched to the optimum load of the tube or transistor with these transformers.