What the chassis does to the sound is one of those things that should be obvious but isn't.

A circuit lives in a physical enclosure. That enclosure vibrates — from airborne sound in the room, from the transformer, from the mechanical energy of the power supply. Those vibrations couple into the electronics through the circuit board, through component leads, through the physical structure of capacitors and resistors. The result is a class of distortion called microphonics: the conversion of unwanted mechanical energy into an electrical signal your system then faithfully amplifies.

This is why enclosure design matters; why in the PMG series we build a chassis within a chassis. Mass helps by raising the resonant frequency and reducing vibration amplitude. Materials and structural elements— the right ones, applied correctly — convert vibrational energy into heat rather than letting it ring through the structure. Decoupling the circuit board from the chassis, and isolating the chassis from the surface beneath it, adds another layer. 

The weight you feel when you pick up one of our components isn't accidental — it reflects decisions about rigidity and resonance control that show up in the listening rather than on a spec sheet. 

The box that holds the circuit is part of the circuit.

And whether you invited it or not, it's always singing along.