Thanks for the info.
Thing is...I'm now quite a few days since putting the MK filter socket in, and I've got to say that the background noise since then really isn't noticeable any longer. At least, not noticeable at the volumes I have my speakers. It certainly wasn't my intention to fit this to solve this problem, but it certainly has had that impact; I had to double check to make sure the earth was sound since the socket change (it is).
Thing is...I'm now quite a few days since putting the MK filter socket in, and I've got to say that the background noise since then really isn't noticeable any longer. At least, not noticeable at the volumes I have my speakers. It certainly wasn't my intention to fit this to solve this problem, but it certainly has had that impact; I had to double check to make sure the earth was sound since the socket change (it is).