The intensity of the magnetic field in a transformer increases as frequency decreases and signal level increases. Therefore, the most demanding job for the transformer is to pass a high-level, low-frequency signal with acceptably low distortion. For example, if too little core material is used, the transformer may magnetically ‘saturate’ (producing very high distortion) at bass frequencies that are at normal signal levels, let alone the higher peak levels associated with instruments like kick drums. This means that even the tiniest, poorly-designed transformer can exhibit low distortion at 1 kHz. In general the ‘level handling’ of a transformer is inversely related to frequency. Jensen rates its transformers very conservatively at 20 Hz, so they will handle even higher levels and have less distortion at higher frequencies. In most of our designs, distortion becomes unmeasurable at frequencies above a few hundred Hz!
Posted in: Transformers