I have a PG&E Smartmeter (by Aclara) 3 feet from my amplifier. My amp makes low humming / rumbling sounds intermittently. They last a short time (3-5 seconds) and are repeated. This goes on 24 hours a day. The sound does not come out of the speakers, but from the amp itself. Could the Smartmeter (which sends and receives an RF signal) be the cause of this? Thanks for any help / information on this. Chris Stevenson