Terminals spade type loosening the binding posts

Try a touch of thread locker (Loctite Blue) on the binding post threads. 

brf:"Try a touch of thread locker (Loctite Blue) on the binding post threads."
I think that is obviously a terrible suggestion that is offered here you do not want to use automotive repair materials on your Music Reproduction System materials such as Loctite cannot possibly be good for your sensitive electrical connections if you're terminals are working themselves loose I would humbly suggest they be replaced with high quality audiophile grade connectors that will not be regularly subject to such outright failure mode.

The thread locker may end up being too strong and cause the posts to loosen on the inside when you try and undo the threads.  There are spring washers made for situations such as this.  There and NOT lock washers but they apply a listed pressure on the nut to prevent them from backing off.  
http://www.globalspec.com/learnmore/mechanical_components/springs/washer_springs

wntrmute2

I'd like very much your suggestion.
The use of spring washer can be probably a very nice solution.

Thanks a lot

brf:"Try a touch of thread locker (Loctite Blue) on the binding post threads."
I think that is obviously a terrible suggestion that is offered here you do not want to use automotive repair materials on your Music Reproduction System materials such as Loctite cannot possibly be good for your sensitive electrical connections if you're terminals are working themselves loose I would humbly suggest they be replaced with high quality audiophile grade connectors that will not be regularly subject to such outright failure mode.

Loctite is not an automobile repair material, but a threaded lock sealer. Loctite is designed for threaded fasteners that are subject to backing out due to vibration.  In addition, Loctite "Blue" is designed to have its seal/lock easily broken for disassembly i.e. not permanent and reversible.  The Loctite is applied sparingly on the binding post thread, and will be not in contact with the spade/binding post interface.