The extremely low value of the dollar at the moment may well have been a factor, certainly I was thinking of it as "only £3,000" last time it was auctioned. Presumably it was the Matusewitch connection that made it go for more this time, it would be more usual for the price to drop the second time around.
Indeed so, it sounds like your 50-key, and Jim's, must also be linked to Gregory Matusewitch... (Though they don't have the provenance that this one had - it does make a difference.)
I emailed the seller to say congratulations and to be put on a list if something happens to this bid winner, the seller emailed me back saying that the US buyer had already paid and it's a done deal! All I can say is WOW, I would have loved to have that beauty for my own. Looks like it is a record holder for ebay! You must admit, the Matusewitch connection helped, although the instrument was a rare find!
LAM
