No, it's the JB's wind, thinner wire, and narrower coils that give it certain total qualities, and sometimes those don't work out as well as one would hope. JB fan here 'Aceman' estimated that 1/3 of the time JB's 'fail' in mahogany. That also means that 2/3's of the time they work out. So it's not that they always bomb out, but that there is a possibility of disappointment. What some members have reported from personal experience in mahogany is a shrill, 'ice pick', 'dentist drill' high-end and a flabby, loose low-end in certain guitars. This doesn't seem to be an issue in brighter woods, where the JB is routinely praised. Can a stock JB work well in mahogany? Absolutely. Can it sound awful? Sometimes. For those that do their own soldering and have some spare PU's lying around (which is most of us here), it's no big deal. We can do what's needed to get the sounds we want. If you're specifically buying a JB for a mahogany guitar and paying someone else to do the work, then you probably want to know about a 1/3 failure rate ahead of time (eve if you return the PU for a refund, you're still paying someone to install and remove, and install again). There's the Custom 'family' of PU's (several production models, and several popular user-modified models) that seem to work well in any kind of wood. That's a safer bet some people. Armed with that knowledge, make your choice.
