Output transformer used in HIFI tube amplifier is a key component in high-fidelity audio equipment, it utilizes electromagnetic induction principle to change the AC voltage of the device, the main components are primary coil, secondary coil and core. In electrical equipment and radio field, commonly used as lifting voltage, matching impedance, safety isolation and so on.
For tube power amplifiers, because loudspeaker is a low impedance element, the power of the high output impedance of tube must be transferred to a low impedance loudspeaker by some means. Usually use audio output transformer, which must be high quality, otherwise we try to improve the quality of amplification will come to naught.
Tube power amplifier circuit is very simple relatively, but if you use output transformer that is produced by different manufacturers to make tube amplifier, the difference of sound is great. When output transformer in the transmission of audio signals, there will be eddy current, hysteresis, magnetic flux leakage and wire resistance loss, while the coil there is impedance, inductance and capacity resistance. These unfavorable factors will also be changed with the frequency of the audio signal changes. Therefore, the quality of the output transformer is related with its core material, quality of its core, enameled wire, winding method, size of the core air gap and so on, those directly affect the sound quality and quality of tube amplifier.
If output transformer output quality is not good, the biggest drawback is large distortion, narrow frequency response, high frequency and low frequency extension is insufficient, midrange is ambiguous, it sounds like tremble can’t achieve high frequency, bass is no powerful, orchestral instruments mixed together , There is no sense of hierarchy, the ensemble is heard is a noisy sound.Therefore, sound quality is a decisive impact output transformer.