Just a followup. I tried to retension the springs in my 300b sockets. It did not work and in the process on of the springs broke. So, I bought some new Azuna sockets from Angela Instruments. Boy what a difference. When I insert the 300b's they do not jiggle one bit. They hold the tube extremely tight and per some comments on the website the tension does not wear out.
I am currently in the process of replacing the old ones (what a tedious job, a lot of patience is required) I will report back once i have the BeePre's up in running.
Richard