I live in Korea and the amp is using the Fender Rumble 100 model. The instrument used is the Roscoe skb 3005 in 2004 (Bartolini pick up-Aguilar obp 3 preamp, 18v Duracell ). The practice time is about 4 hours a day. By the way, when you see the battery replacement time of other Aguilar obp 3 users, it is said that they replace it every three to six months. But my bass is after a month, the bass guitar sound fades, or the volume decreases overall, so I adjust the volume on the amplifier. There is no way to check the remaining capacity of the battery, so I'm worried about it every time I perform. (Always carry two 9v batteries and a screwdriver in your bag) 1 . Do I have to go to the guitar center and have my preamplifier checked? 2. Or is it a preamplifier with a faster battery drain? 3. Bass Guitar Boosting your bass, treble, or middle sounds in your preamplifier will drain your battery faster?