Khandu, are you sure it's German? Bed manufacturers in Mittenvald have been known to stick labels under the mattress provenancing the truckle as made in Cremona, where the very Stradivarius of night furniture have long been manufactured. Chances are that you could have a genuine Amati Bed Company classic on your hands, which is old enough to have springs that have rusted from the steam of night soil convecting from the carpet vase. I can't believe that you are still using such a valuable asset for its original purpose. You can play on a cheap Chinese bed and still get squeaks. I understand it's all in the wrist.