Like Folkvangr, the Schiit Valhalla 3 operates as a OTL/OCL design—no output transformers, no capacitors in the signal path.

The best tech products announced this week include Bang & Olufsen's portable speaker and Leica's special-edition camera.

This process simulates nearly every tube, preamp, and transformer, creating a fully digital “twin” made up of ones and zeros. In both cases, the goal is to take an instrument’s signal ...