If you check the archives you'll find that it was Pat Missin who first developed the ultrasuede (or as he calls them, microfibre) valves that have been mentioned. He then showed these to P.T. Gazell at a convention and P.T. took to them rather quickly. Which makes sense, because when Pat used them on the customized 280 he did for me before all this, I immediately decided they were the best valves I'd yet tried. And I'd tried everything (teflon, micropore, etc...), except leather.
They can have some problems in the lowest range of a 280, but I haven't tried a spring system yet to fix that. Overall they simply work and don't give problems. I notice no significant change in attack or tone whatsoever; if they weren't sealing properly I don't think you'd have a softer attack or mellower tone, you'd have noticeable leakage. But this is hard to determine since all the harps I have these valves on have been worked on by Pat, so are significantly far from standard and I can make no real comparisons (and have no desire to remove these valves and put on others for a test). However, I have noticed that they will droop some over time depending on how you store the harmonica. I suggest always storing a harmonica with these valves on it's end (either mouthpiece or opposite) as this way the valves will not be effected by gravity and droop. This isn't a major problem, just something to be aware of.
Hope this helps.
()() JR "Bulldogge" Ross () () `----'
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