Antony Dannecker many years ago made a C super 64 to Bb
by adding solder to the reeds, a method I know also used by john cook
to make one for a customer who attended one of his all day chromatic workshops
alongside me.
anthomp
Exactly. I know that's how most of those who convert C's to Bb's do it, thank you. John is a Highly rated English customizer/player/teacher...but other
technicians I know here in the States do it the same way. I was going to have two of my own Super 64's converted to keys of A and Bb by one of our
best customizers (now retired from doing this kind of work), so someone else is taking over the process. Neither of us is in a rush.
Fwiw, Robert Bonfiglio talked about tuning one of his own 16-hole chromatics to a B down from a C to record a specific tune, by using solder. It took
him a long time but he did it by himself.
Brendan Power made some 16-hole Bb's and A's when he 'frankensteined' cx-12's by cutting them apart, soldering and gluing two instruments together to come up with his fantastic creations.
Bends Tonica actually produced 16-hole A's and Bb's for a while --I only found out about them when they were being discontinued, much to my chagrin, since I've long-since wanted both. Unsure if I had the funds at the time anyway.
Separately, we do know via word-of-mouth that Hohner produced 16-hole Bb (and possibly A's) for some of the top players 'back in the day'. They weren't discussed because we were all supposed to believe that the ultimate achievement was to play every key on a single instrument and if one of our heroes
was actually using a different-keyed instrument to play specific songs (or more difficult tunes) the world would come to an end (or some such)?

scotty