I've used the JRC parts for years and they don't need a load to be stable. I've never seen them be bothered by the input voltage at all but I've never put 30VDC into them. If the amp is stuck at the rails then something is very wrong, blown transistors or solder bridges being the most likely issues. Well that and flux, that can fuck up everything at these voltage levels. Glad it helped, took a while to figure out what the hell was going on with the circuit. As for the servo, the OP27 is bloody slow to work and some can be a bit off. Personally I never use them.