I know it's come up in conversation here a few times whether it's OK to use Kevlar bottom heads on
Yamaha (and other) drums. I just stumbled across the official word from
Yamaha in their most recent catalog and figured I'd share.
I've attached the image from the catalog containing the quote, and copied the text below for more convenient reading.
All Yamaha SFZ marching drums are covered by Yamaha's exclusive "Hoop-to-Feet" two-year warranty. Should any part of the drums be defective, Yamaha will replace the defective portion free of charge (provided a snare side Kevlar head is not utilized).
...not to say that the drums can't handle Kevlar heads. It just gives
Yamaha a potential excuse for voiding the warranty if something breaks.