[TenTec] Corsair ,help with cw filter!

[g p]

Installed the 217 cw filter in my Corsair 1 but when switched to the filter position the gain drops considerably and there is white noise, I also tried a different 217 and the same thing lots of white noise and only the stronger signals are heard, the weaker signals disappear in the white noise and this is with the preamp on, also while in the narrow mode the PBT does not function at all. This does not happens in my Omni D-B or my Argosy.
 
Any thoughts?
 
Thanks, Gil