Double Bass AMT SP25B mic and Underwood pickup

[Sergio Barrozo]

I would like to buy the AMT SP25B comes with a preamp with two balanced outputs. But it has only one input.
How can I use the AMT mic together with an underwood pickup?

 

[Tom Baldwin]

You will need a two-channel head or a two-channel preamp like the D-Tar Solstice. The AMT box is not a preamp as much as it is a signal processor and phantom power source for the mic.