What is the Input Impedance of the ISA 428 MkII?

Line Input: 10kΩ

Inst Input: >1MΩ

Mic Input:

Pressing the Z In switch steps through each of the four transformer pre-amp input impedance values, as indicated
by the corresponding LEDs. By selecting different values for the impedance of the ISA 428 MkII transformer input, the
performance of both the ISA 428 MkII pre-amp and the microphone connected can be tailored to set the desired level and
frequency response. The impedance values are as follows:

Low – 600Ω

ISA 110 – 1k4Ω

Med – 2k4Ω

High – 6k8Ω