Wierd Imaging Problem

I have a problem with imaging in stereo and in movies.My right speaker is not as detailed than the left.When swapping speakers the problem stays to the right speaker.

The soundstage all sounds correct.The voice is in the middle and nevers goes to the left or right of center.The left speaker sounds detailed and the right has a loss of detail whether in stereo or for movies.

I have changed all wiring and IC's.No change.

Now for the starngest part of all.The loss of detail in the right speaker is always present on all sources when I first turn everything on.After awhile and it may take a hour ,the right speaker comes back into focus and the loss of detail is not present.There is no pop or clicks it just becomes correct. I have another set of speakers that I used to tst with and the same thing happens.

I have another receiver that if I use it, it still happens with that receiver .Both of my receivers are around 10 years old.I have bassically replaced everything but still get the same problem.

I am down to thinking that both receivers are going bad.Unlikely but possible.

One of the receivers had a center channel going out and I re-soldered the relay on that receiver along with a lot of other solder joints so maybe I damaged something on that receiver.I then bought the other receiver used for testing my problem only to have the same problem.At a loss here guys.Any help appreciated.