The Strengths and Limitations of the Audio Transformer
Audio transformer is specifically designed for use in audio circuits. Audio transformer can be used to block radio frequency interference or the DC component of an audio signal, to split or combine audio signals, or to provide impedance matching between high and low impedance circuits.
Audio transformer was originally designed to connect different telephone systems to one another while keeping their respective power supplies isolated, and are still commonly used to interconnect professional audio systems or system components.
Being magnetic devices, audio transformers are susceptible to external magnetic fields such as those generated by AC current-carrying conductors. Audio transformers used for low-level signals, such as those from microphones, often include shielding to protect against extraneous magnetically coupled signals.
Audio transformers have limitations on the amount of sound decibels they can handle. They have limited frequency responses. Audio transformers can block signals only below the range of 20-20,000 hertz. There is a maximum input level and this level cannot be exceeded without damaging the transformer and this point is called its saturation point. Audio transformers cannot set up a signal of more than 25 decibels of sound.
A good audio transformer should be capable of matching impedances. It should be able to increase or decrease signal level for up to 25 decibels. It should effectively isolate problem components in a group of audio devices. It should have a flat and broad frequency response. A hotter signal should go through the transformer without saturating it. A good audio transformer will have a good shield. Shields are necessary so that the audio device will not pick up any hum or sound from other devices.