The recommended minimum voltage for all MyLocoSound soundcards is 7.2v. You may be able to run at lower voltages but are running the risk of sound interruptions. When you sound a horn or whistle at high volume that pulls more current and may drag the voltage down below the shut off level. Therefore we recommend 7.2v upwards.Peter, what is the recommended minimum voltage for a MLS, I know your website shows a 9 volt battery for track power, but Fosworks informs that 6 volts is the recommended minimum voltage.
Regards
Peter Lucas
MyLocoSound