I've had a good few listening sessions this week.
I've tried classical, pop, rock, electronic, old & new music.
The only negative is the reduces bass quantity.
I feel this has been made up for with all the other positive improvements.
Its difficult to describe the sound comparison but I'll have a go.
The bass does not seem as deep or powerful BUT seems faster and bass tunes can be followed more easily.
Some instruments are much more obvious but nicely separated so everything that was there before is still there but with more added.
Voices are much clearer and 'nicer', more natural.
Where high frequencies were prominent they are more so but nicer without fatigue.
I can turn the volume up more without complaints from downstairs so the pre-amp is doing more of the work.
At about maximum listening levels that I would regularly use the amp it gets slightly warn, not hot so it has lots more oomph left in it.