OEP Z16 Series Audio Transformers The OEP Z16 range of audio transformers are constructed with an interwinding screen and centre tap. Various different impedance ratios are available, and these audio transformers can be used in reverse with the centre tap on the primary. Z16 audio transformers are low power and suitable for PCB mounting. Product Application Information Recommended applications for these audio transformers include ground loop isolating microphone inputs and impedance matching.