Man, this is an eye opener! I use these cheapy GP Alkalines (chinese) that I can get for 100yen a 4 X AA pack or 1 X 9V for 150yen. Been using them since I have been here and never had an issue. Maybe a letter to them would be prudent! In the US I ususally buy Duracells (ultras are awesome) but use those Ikea (repackaged Vartas) that you can get 8 X AA for $2, those have never been a problem either. I have had NiMH that have been failing despite complete discharge and charge cycles.....2000mAH Energizers (made in Japan no less) and 9V 150mAH Rayovac (chinese). Lately these 9V Ultralife Lithiums are what I have been using in the Sax. In fact, there is a UK vendor selling them for $40/10pack delivered (if you are in the UK, it is 20quid). You can get like 14 plus hours out of them!