Philco 77

[Electronic M]

Shielding is indeed very important, especially in TRF sets. Any feedback that can happen will happen and will produce distortion and funny noises. <--Murphy's Law of TRF.
Shielding prevents feedback and interference.

If you get it shielded up and there is still distortion pull the detector tube and inject audio downstream of it...Remember HiFi wasn't a thing until the late 30's (and then was only a thing on high-end sets). If speech is reasonably understandable it is probably about right. That Philco dates from a time where having a paper cone loudspeaker was a new technology just being grasped by manufacturers.