Audio Transformers
600: 2K4 dual step-up transformer PT25 is used for mobile phone computer MP3 to enhance analog taste and eliminate digital sound

Actual measurement:
The primary 10K inductance is about 72-86H, and the copper resistance is about 438
The secondary 40K inductance is about 170-200H, and the copper resistance is about 870.
Transformer power is about 3W.
The primary and secondary can exceed 25mA audio current, and the large signal current is not overloaded or clipped, which is much stronger than E25 permalloy.
Frequency response width:
10HZ--48KHZ attenuation-2.4DB
20HZ--45KHZ attenuation-1.6DB