The ignition comes from the engine alternator/generator so this is not done by the converters. But those do make noise, also the gyro of the stby AI makes sound as wel as the altimeter (internally a small hamer is 'tapping' on the bellow of the altimeter just like you would do on a barometer). The fuel pumps only run when main power is on the jet, so they will not run unless external power is applied or after the Main Gen is online..
