http://wbsps.kuzub.com/
http://wbsps.kuzub.com/manuals.htm
http://wbsps.kuzub.com/PDFs/M470A%20Input%20Module.pdf
Power requirements: +/-25 volts dc, 20mA nominal, 80mA maximum
Peeping the module plan, it is very slightly voltage-sensitive. +/-24V will be fine. +/-18V should work fine. +/-12V gives up headroom and also gets you into a trace of crossover distortion (WBS biased output pairs with resistors instead of diodes).
By the specs, you "could" need 2*80mA = 160mA for a pair. But that could only happen with 600R load on the Insert and a totally-clipped signal. I can't see how even "normal overload" could ever exceed 100mA/pair.
A +/-24V 100mA supply should be easy to turn up.