I've heard of bass eating bull frogs and tadpoles ,but was wondering if it would be worth my time to put salamanders in my pond as a way to fatten my bass.

IMO they wouldn't last very long in your pond. The last time I tried to use salamanders for catfish I couldn't get the salamander to hit the bottom before a bass ate it. Two dozen large tiger salamanders were gone in 30 minutes.

I have the impression that salamander reproduction is less robust and more tenuous than that of frogs and toads.