In a preferred embodiment, a Sine Amplitude Converter ("SAC") method and apparatus for VTMs converts a DC input voltage to a DC output voltage using a fixed transformation ratio at a frequency locked to a resonance. The SAC uses a resonant circuit including a transformer and complementary primary switches operating with balanced switching and a high power conversion duty cycle (e.g., above 94%) to perform high frequency, low noise, single stage power processing. The resonant circuit may have a low Q while enhancing conversion efficiency. Common-mode noise may be effectively reduced using symmetrical resonant power trains.In a preferred embodiment, a low profile (<0.16 inch high), low permeability "dog's bones" core structure, integrated with multi-layer PCB windings to complete SAC transformers, gives rise to a VTM manufacturing platform with greater than 400 Watts/cubic-inch power density and 95% efficiency, converting 100 150 Watts at the point of load. Capable of low manufacturing costs, this enabling technology supports flexible, molded packages for VTMs, which are characteristic of large IC's or "System In a Package" ("SIP") devices, as distinct from the standard "bricks" characteristic of the DC-DC converters, the workhorses of vintage Distributed Power Architecture ("DPA").