Moms love Mannheim Steamroller. That’s not a terrible thing for the Chip Davis-led electric orchestra, as this die-hard fan group has helped the band sell 28 million albums in America alone since its inception in 1974. Most famous for their ’80s-sounding take on Christmas songs, Mannheim Steamroller has music for other holidays as well — not that anyone really cares about that. Coming to the Lilac City next Wednesday, the group will delight mothers and their loved ones brought along for the ride, with their almost campy but thoroughly entertaining Christmas tunes. So what if we haven’t even had Thanksgiving yet.