I've got a restored 1930s amperite ribbon mic. It's got a new ribbon motor and new 1.8 micron thick ribbon but original transformer. The mic seems to be lacking low end I originally bought it because I thought it was going to have a huge old school vintage vibe but it sounds kind of hollow. I'm using it through a high impedance in line gain booster. What could be the cause of the low end loss? Original transformer?