Iain.
Depends how confident you are with a soldering iron. The board has survived a couple of attacks from me, but there's always a danger of lifting PCB tracks.
The ceramic surface mounts are reckoned to be good with digital so i'd just bypass em for the time being.
The input cap C9(another ceramic which doesn't sound bad) can be improved on. I've been doing an experiment with different bypass caps for C9. Haven't really finished yet,(been at it for a week or so) but have discovered that some caps which can sound wonderful in analogue applications, don't seem to cope with high frequency digital information.
Exceptions are Obbligatto caps and Vishay/ERO 1837 which live up to expectation. Both of these improve on the original. Even a cheap tantalum sounded quite nicely balanced.
I tried a red Wima here but it sounded muffled especially at the bottom end.
Anything polyester sounded awful.
The clear winner amongst those tested so far, would have been a 0.33uf Ansar polyprop which has stunning clarity at the top end, but in this application, very weak bass.
Of course you may find that different values yield better results, but i have a feeling that very low inductance is important here and that's why the big Obbligatto cap works better than other big caps.
I even tried bypassing the bypass cap in an effort to get a good compromise, but then things start to deteriate. To be expected.
Next step is to remove the original C9 and see which one works best in its place.
Good luck.:)
