Audio transformers, power supply transformers and chokes are wound on c-cores. Compared to EI cores, c-cores are more efficient electromagnetically, yielding better quality transformers. Furthermore, c-core transformers use straight bobbins to allow very precise winding techniques, especially important in push-pull transformers with center-taps. This precision is hardly possible using toroidal cores. Audio transformers using c-cores sound open and homogeneous. Core material is grain oriented silicon steel (lamination thickness from 0,1mm to 0,35mm). Amorphous alloy c-cores are used for absolutely top level transformers. Precise and dedicated winding techniques are applied to guarantee optimum bandwidth and signal transfer. Chokes are very effective in reducing power supply ripple. C-core based chokes are more efficient than EI-core based chokes in suppressing higher frequency power line pollution. Chokes are wound in isolated layers for minimal capacitance. Power supply transformers are wound on c-cores as well. These transformers are low temperature with minimal strayfields. Resonances are absent. Electrostatic shields are applied to reduce transfer of power line pollution. Center taps are very precise as a result of symmetrical winding techniques. A high quality power supply transformer is the real starting point for a high quality amplifier!