the Linear PSU´s have on startup some issues to bring both voltages (-15/+15V) at the same time, in result the voltage regulators blows on obx.
in my modular system i have on high load similar issue with this rootcause..
(picture from http://www.modularsynthesis.com/modules/DJB-power/djbpower.htm )
Hint for calibrate the Voicecards:
The both multiturn pots must be adjusted to 61K.