I have as a system a Luxman RV-371 5.1 amplifier connected to a pair of Wharfedale E70's and a pair of Wharfedale W70d MIII speakers. I am happy with the sound it produces. I cannot find anything in a search for RV371 so I thought I would post here. What I have noticed since I got this amp is the memory for radio station presets is not working. I assume it is an old battery that has failed. Can anyone tell me what type of battery to buy as a replacement?