Stereo Phono Pre-Amplifier (420-2111) Battery Faxback Doc. # 6624 The pre-amplifier requires one 9-volt battery. We recommend an alkaline battery, such as Radio Shack Cat. no. 25-553. 1. Lift the battery compartment cover. 2. Snap the battery into the terminals and insert the battery into the compartment. 3. Replace the cover. When the sound quality weakens, replace the battery. (CJD/all-08/17/94)