It was available for collection yesterday and I picked it up this morning. I was told it is a brand new replacement but in fact the 'repair mark' is quite obvious, it's like tool mark between the glass and the frame. Never mind I didn't expect a brand new replacement anyway.
Tested it thoroughly tonight, still disappointed, the sound quality has improved a bit but the broken speaker sound for certain songs is still obvious. My proof is using my iPod Photo to compare playing the same songs. The trouble is that so far I found bad sound is heard only with this album Best Audiophile Voices Selection. I love this so much that I play it all the time. It is OK for my other favorite album such as Carpenters even if I push the volume to the limit.
The service man said this could be a loosen jack to my ears this is like resonance at high pitch (both vocal and piano) of those songs on the jack assembly. I couldn't find any other songs in my library of near 1,000 songs that could produce that sort of bad sound yet.
Perhaps it's faulty by design I'll give up because it isn't obvious unless I'm listening in a very quite environment.