Aha!! Mr Science and i are very recently acquainted π ive been using the cobalt flats on my Yamaha BB 424 for nearly three months now and I'm a big fan! They are very bright for a flat and seem to have a more musical sweet treble than Chromes which have a lot of high mids clank. They instantly reminded me of a slightly worn in set of nickel rounds!!! They also have a fairly low tension (mine are 105-45) and are the first flats I've been able to get a convincing slap tone! They do have a nice growl in the mids, the bottom end however isn't the same as standard flats but mine have worn in and warmed up,still with a lot of clarity. I was very close to buying the Dunlop flats on camerons recommendation but I took a chance and was very pleased π
I'm very tempted to put a set on my old jazz too but it loves high beams too much π