I recently sold a customer a brand new LGB 28446 Class Ge 4/4 II locomotive with the Marklin mfx/dcc sound decoder. It was produced from the Marklin factory's recent production run of these locomotives. When my customer tested the locomotive on his roller wheels test track using his Massoth 12 Amp Command Station/Massoth 12 Amp Power Supply and Massoth wireless 2.4GHz Navigator, he's getting some low background popping noise. This issue has been referred to the Marklin factory for a response. In the meantime, I'm wondering if any other hobbyists have experienced this popping sound coming out through the sound system with recent production LGB locomotives with their factory mfx/dcc sound decoders.