Units undergo a three-level QC process that includes: (1) Careful testing of all components and assembled boards; (2) Testing of units immediately following assembly, (3) A strict 48 - 72 hour burn-in process. Final steps include a double-check of bias and offset, oscilloscope and spectral analyzer testing, and individual listening tests on our reference system. All transformers are specifically designed for the amplifier in partnership with Plitron engineers. All output transistors are measured and matched to within 1%. Reference-grade Audio Selection dampers are included as standard!!. These "feet" provide resonance control and surface de-coupling. Heavy-duty gold-plated WBT connectors are standard as are Neutrik XLR connectors.