I am running a s.i. T-amps off a 12v sla battery (well Two actually) and am trying to add a line level pre amp to the system. Is it possible to run both the preamp and the tamp from the same 12v batteries? So far NO, when both the t amp and the pre amp are connected to separate batteries I get sound but hooked to the same batteries get power indicator leds but no sound. I can run the pre' and the t amp off separate batteries and it works. I've tried putting both batteries in parallel same no sound result. any advice on how to trouble shoot this and if it is possible to run both T and pre from the same 12v supply. the pre amp is a very simple one (stereo line level booster tc-780LC from phono preamps .com, built with a 553NP Op-Amp.