I think you are all correct; metal to metal ringing was messing it up. I am going to figure out some rubber interface between the weight and the preamp.
I am curious if anyone has any thoughts on the shaking of my building (from surrounding traffic and such). Don't try to figure out 'why' it is happening. The question is how to treat my system so that excess vibrations can be dealt with. I have found that the very fine micro vibrations probably harm sound more than out and out floor shaking. After all, the vibrations from fairly loud music are way more profound than the shaking of my building.
I am curious if anyone has any thoughts on the shaking of my building (from surrounding traffic and such). Don't try to figure out 'why' it is happening. The question is how to treat my system so that excess vibrations can be dealt with. I have found that the very fine micro vibrations probably harm sound more than out and out floor shaking. After all, the vibrations from fairly loud music are way more profound than the shaking of my building.